diff --git a/Documentation/gpu/drm-internals.rst b/Documentation/gpu/drm-internals.rst
index d218dd29221a..dd28e39cf966 100644
--- a/Documentation/gpu/drm-internals.rst
+++ b/Documentation/gpu/drm-internals.rst
@@ -204,6 +204,15 @@ drm_device <drm_device>` irq_enabled field to 1 upon
 registration of the IRQs, and clear it to 0 after unregistering the
 IRQs.
 
+IRQ Helper Library
+~~~~~~~~~~~~~~~~~~
+
+.. kernel-doc:: drivers/gpu/drm/drm_irq.c
+   :doc: irq helpers
+
+.. kernel-doc:: drivers/gpu/drm/drm_irq.c
+   :export:
+
 Memory Manager Initialization
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst
index bfecd21a8cdf..2d77c9580164 100644
--- a/Documentation/gpu/drm-kms.rst
+++ b/Documentation/gpu/drm-kms.rst
@@ -612,8 +612,8 @@ operation handler.
 Vertical Blanking and Interrupt Handling Functions Reference
 ------------------------------------------------------------
 
-.. kernel-doc:: include/drm/drm_irq.h
+.. kernel-doc:: include/drm/drm_vblank.h
    :internal:
 
-.. kernel-doc:: drivers/gpu/drm/drm_irq.c
+.. kernel-doc:: drivers/gpu/drm/drm_vblank.c
    :export:
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index c156fecfb362..acc88942c2e5 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -16,7 +16,7 @@ drm-y       :=	drm_auth.o drm_bufs.o drm_cache.o \
 		drm_framebuffer.o drm_connector.o drm_blend.o \
 		drm_encoder.o drm_mode_object.o drm_property.o \
 		drm_plane.o drm_color_mgmt.o drm_print.o \
-		drm_dumb_buffers.o drm_mode_config.o
+		drm_dumb_buffers.o drm_mode_config.o drm_vblank.o
 
 drm-$(CONFIG_DRM_LIB_RANDOM) += lib/drm_random.o
 drm-$(CONFIG_DRM_VM) += drm_vm.o
diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h
index bca2c66c5d28..6a0cbcc84534 100644
--- a/drivers/gpu/drm/drm_internal.h
+++ b/drivers/gpu/drm/drm_internal.h
@@ -54,8 +54,9 @@ int drm_name_info(struct seq_file *m, void *data);
 int drm_clients_info(struct seq_file *m, void* data);
 int drm_gem_name_info(struct seq_file *m, void *data);
 
-/* drm_irq.c */
+/* drm_vblank.c */
 extern unsigned int drm_timestamp_monotonic;
+void drm_vblank_disable_and_save(struct drm_device *dev, unsigned int pipe);
 
 /* IOCTLS */
 int drm_wait_vblank(struct drm_device *dev, void *data,
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index c7debaad67f8..28d736c3fcb4 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -3,6 +3,25 @@
  *
  * \author Rickard E. (Rik) Faith <faith@valinux.com>
  * \author Gareth Hughes <gareth@valinux.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
  */
 
 /*
@@ -32,429 +51,15 @@
  * OTHER DEALINGS IN THE SOFTWARE.
  */
 
+#include <drm/drm_irq.h>
 #include <drm/drmP.h>
-#include "drm_trace.h"
-#include "drm_internal.h"
 
 #include <linux/interrupt.h>	/* For task queue support */
-#include <linux/slab.h>
 
 #include <linux/vgaarb.h>
 #include <linux/export.h>
 
-/* Retry timestamp calculation up to 3 times to satisfy
- * drm_timestamp_precision before giving up.
- */
-#define DRM_TIMESTAMP_MAXRETRIES 3
-
-/* Threshold in nanoseconds for detection of redundant
- * vblank irq in drm_handle_vblank(). 1 msec should be ok.
- */
-#define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000
-
-static bool
-drm_get_last_vbltimestamp(struct drm_device *dev, unsigned int pipe,
-			  struct timeval *tvblank, bool in_vblank_irq);
-
-static unsigned int drm_timestamp_precision = 20;  /* Default to 20 usecs. */
-
-/*
- * Default to use monotonic timestamps for wait-for-vblank and page-flip
- * complete events.
- */
-unsigned int drm_timestamp_monotonic = 1;
-
-static int drm_vblank_offdelay = 5000;    /* Default to 5000 msecs. */
-
-module_param_named(vblankoffdelay, drm_vblank_offdelay, int, 0600);
-module_param_named(timestamp_precision_usec, drm_timestamp_precision, int, 0600);
-module_param_named(timestamp_monotonic, drm_timestamp_monotonic, int, 0600);
-MODULE_PARM_DESC(vblankoffdelay, "Delay until vblank irq auto-disable [msecs] (0: never disable, <0: disable immediately)");
-MODULE_PARM_DESC(timestamp_precision_usec, "Max. error on timestamps [usecs]");
-MODULE_PARM_DESC(timestamp_monotonic, "Use monotonic timestamps");
-
-static void store_vblank(struct drm_device *dev, unsigned int pipe,
-			 u32 vblank_count_inc,
-			 struct timeval *t_vblank, u32 last)
-{
-	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
-
-	assert_spin_locked(&dev->vblank_time_lock);
-
-	vblank->last = last;
-
-	write_seqlock(&vblank->seqlock);
-	vblank->time = *t_vblank;
-	vblank->count += vblank_count_inc;
-	write_sequnlock(&vblank->seqlock);
-}
-
-/*
- * "No hw counter" fallback implementation of .get_vblank_counter() hook,
- * if there is no useable hardware frame counter available.
- */
-static u32 drm_vblank_no_hw_counter(struct drm_device *dev, unsigned int pipe)
-{
-	WARN_ON_ONCE(dev->max_vblank_count != 0);
-	return 0;
-}
-
-static u32 __get_vblank_counter(struct drm_device *dev, unsigned int pipe)
-{
-	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
-		struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
-
-		if (crtc->funcs->get_vblank_counter)
-			return crtc->funcs->get_vblank_counter(crtc);
-	}
-
-	if (dev->driver->get_vblank_counter)
-		return dev->driver->get_vblank_counter(dev, pipe);
-
-	return drm_vblank_no_hw_counter(dev, pipe);
-}
-
-/*
- * Reset the stored timestamp for the current vblank count to correspond
- * to the last vblank occurred.
- *
- * Only to be called from drm_crtc_vblank_on().
- *
- * Note: caller must hold &drm_device.vbl_lock since this reads & writes
- * device vblank fields.
- */
-static void drm_reset_vblank_timestamp(struct drm_device *dev, unsigned int pipe)
-{
-	u32 cur_vblank;
-	bool rc;
-	struct timeval t_vblank;
-	int count = DRM_TIMESTAMP_MAXRETRIES;
-
-	spin_lock(&dev->vblank_time_lock);
-
-	/*
-	 * sample the current counter to avoid random jumps
-	 * when drm_vblank_enable() applies the diff
-	 */
-	do {
-		cur_vblank = __get_vblank_counter(dev, pipe);
-		rc = drm_get_last_vbltimestamp(dev, pipe, &t_vblank, false);
-	} while (cur_vblank != __get_vblank_counter(dev, pipe) && --count > 0);
-
-	/*
-	 * Only reinitialize corresponding vblank timestamp if high-precision query
-	 * available and didn't fail. Otherwise reinitialize delayed at next vblank
-	 * interrupt and assign 0 for now, to mark the vblanktimestamp as invalid.
-	 */
-	if (!rc)
-		t_vblank = (struct timeval) {0, 0};
-
-	/*
-	 * +1 to make sure user will never see the same
-	 * vblank counter value before and after a modeset
-	 */
-	store_vblank(dev, pipe, 1, &t_vblank, cur_vblank);
-
-	spin_unlock(&dev->vblank_time_lock);
-}
-
-/*
- * Call back into the driver to update the appropriate vblank counter
- * (specified by @pipe).  Deal with wraparound, if it occurred, and
- * update the last read value so we can deal with wraparound on the next
- * call if necessary.
- *
- * Only necessary when going from off->on, to account for frames we
- * didn't get an interrupt for.
- *
- * Note: caller must hold &drm_device.vbl_lock since this reads & writes
- * device vblank fields.
- */
-static void drm_update_vblank_count(struct drm_device *dev, unsigned int pipe,
-				    bool in_vblank_irq)
-{
-	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
-	u32 cur_vblank, diff;
-	bool rc;
-	struct timeval t_vblank;
-	int count = DRM_TIMESTAMP_MAXRETRIES;
-	int framedur_ns = vblank->framedur_ns;
-
-	/*
-	 * Interrupts were disabled prior to this call, so deal with counter
-	 * wrap if needed.
-	 * NOTE!  It's possible we lost a full dev->max_vblank_count + 1 events
-	 * here if the register is small or we had vblank interrupts off for
-	 * a long time.
-	 *
-	 * We repeat the hardware vblank counter & timestamp query until
-	 * we get consistent results. This to prevent races between gpu
-	 * updating its hardware counter while we are retrieving the
-	 * corresponding vblank timestamp.
-	 */
-	do {
-		cur_vblank = __get_vblank_counter(dev, pipe);
-		rc = drm_get_last_vbltimestamp(dev, pipe, &t_vblank, in_vblank_irq);
-	} while (cur_vblank != __get_vblank_counter(dev, pipe) && --count > 0);
-
-	if (dev->max_vblank_count != 0) {
-		/* trust the hw counter when it's around */
-		diff = (cur_vblank - vblank->last) & dev->max_vblank_count;
-	} else if (rc && framedur_ns) {
-		const struct timeval *t_old;
-		u64 diff_ns;
-
-		t_old = &vblank->time;
-		diff_ns = timeval_to_ns(&t_vblank) - timeval_to_ns(t_old);
-
-		/*
-		 * Figure out how many vblanks we've missed based
-		 * on the difference in the timestamps and the
-		 * frame/field duration.
-		 */
-		diff = DIV_ROUND_CLOSEST_ULL(diff_ns, framedur_ns);
-
-		if (diff == 0 && in_vblank_irq)
-			DRM_DEBUG_VBL("crtc %u: Redundant vblirq ignored."
-				      " diff_ns = %lld, framedur_ns = %d)\n",
-				      pipe, (long long) diff_ns, framedur_ns);
-	} else {
-		/* some kind of default for drivers w/o accurate vbl timestamping */
-		diff = in_vblank_irq ? 1 : 0;
-	}
-
-	/*
-	 * Within a drm_vblank_pre_modeset - drm_vblank_post_modeset
-	 * interval? If so then vblank irqs keep running and it will likely
-	 * happen that the hardware vblank counter is not trustworthy as it
-	 * might reset at some point in that interval and vblank timestamps
-	 * are not trustworthy either in that interval. Iow. this can result
-	 * in a bogus diff >> 1 which must be avoided as it would cause
-	 * random large forward jumps of the software vblank counter.
-	 */
-	if (diff > 1 && (vblank->inmodeset & 0x2)) {
-		DRM_DEBUG_VBL("clamping vblank bump to 1 on crtc %u: diffr=%u"
-			      " due to pre-modeset.\n", pipe, diff);
-		diff = 1;
-	}
-
-	DRM_DEBUG_VBL("updating vblank count on crtc %u:"
-		      " current=%u, diff=%u, hw=%u hw_last=%u\n",
-		      pipe, vblank->count, diff, cur_vblank, vblank->last);
-
-	if (diff == 0) {
-		WARN_ON_ONCE(cur_vblank != vblank->last);
-		return;
-	}
-
-	/*
-	 * Only reinitialize corresponding vblank timestamp if high-precision query
-	 * available and didn't fail, or we were called from the vblank interrupt.
-	 * Otherwise reinitialize delayed at next vblank interrupt and assign 0
-	 * for now, to mark the vblanktimestamp as invalid.
-	 */
-	if (!rc && in_vblank_irq)
-		t_vblank = (struct timeval) {0, 0};
-
-	store_vblank(dev, pipe, diff, &t_vblank, cur_vblank);
-}
-
-static u32 drm_vblank_count(struct drm_device *dev, unsigned int pipe)
-{
-	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
-
-	if (WARN_ON(pipe >= dev->num_crtcs))
-		return 0;
-
-	return vblank->count;
-}
-
-/**
- * drm_accurate_vblank_count - retrieve the master vblank counter
- * @crtc: which counter to retrieve
- *
- * This function is similar to @drm_crtc_vblank_count but this
- * function interpolates to handle a race with vblank irq's.
- *
- * This is mostly useful for hardware that can obtain the scanout
- * position, but doesn't have a frame counter.
- */
-u32 drm_accurate_vblank_count(struct drm_crtc *crtc)
-{
-	struct drm_device *dev = crtc->dev;
-	unsigned int pipe = drm_crtc_index(crtc);
-	u32 vblank;
-	unsigned long flags;
-
-	WARN(!dev->driver->get_vblank_timestamp,
-	     "This function requires support for accurate vblank timestamps.");
-
-	spin_lock_irqsave(&dev->vblank_time_lock, flags);
-
-	drm_update_vblank_count(dev, pipe, false);
-	vblank = drm_vblank_count(dev, pipe);
-
-	spin_unlock_irqrestore(&dev->vblank_time_lock, flags);
-
-	return vblank;
-}
-EXPORT_SYMBOL(drm_accurate_vblank_count);
-
-static void __disable_vblank(struct drm_device *dev, unsigned int pipe)
-{
-	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
-		struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
-
-		if (crtc->funcs->disable_vblank) {
-			crtc->funcs->disable_vblank(crtc);
-			return;
-		}
-	}
-
-	dev->driver->disable_vblank(dev, pipe);
-}
-
-/*
- * Disable vblank irq's on crtc, make sure that last vblank count
- * of hardware and corresponding consistent software vblank counter
- * are preserved, even if there are any spurious vblank irq's after
- * disable.
- */
-static void vblank_disable_and_save(struct drm_device *dev, unsigned int pipe)
-{
-	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
-	unsigned long irqflags;
-
-	assert_spin_locked(&dev->vbl_lock);
-
-	/* Prevent vblank irq processing while disabling vblank irqs,
-	 * so no updates of timestamps or count can happen after we've
-	 * disabled. Needed to prevent races in case of delayed irq's.
-	 */
-	spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
-
-	/*
-	 * Only disable vblank interrupts if they're enabled. This avoids
-	 * calling the ->disable_vblank() operation in atomic context with the
-	 * hardware potentially runtime suspended.
-	 */
-	if (vblank->enabled) {
-		__disable_vblank(dev, pipe);
-		vblank->enabled = false;
-	}
-
-	/*
-	 * Always update the count and timestamp to maintain the
-	 * appearance that the counter has been ticking all along until
-	 * this time. This makes the count account for the entire time
-	 * between drm_crtc_vblank_on() and drm_crtc_vblank_off().
-	 */
-	drm_update_vblank_count(dev, pipe, false);
-
-	spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
-}
-
-static void vblank_disable_fn(unsigned long arg)
-{
-	struct drm_vblank_crtc *vblank = (void *)arg;
-	struct drm_device *dev = vblank->dev;
-	unsigned int pipe = vblank->pipe;
-	unsigned long irqflags;
-
-	spin_lock_irqsave(&dev->vbl_lock, irqflags);
-	if (atomic_read(&vblank->refcount) == 0 && vblank->enabled) {
-		DRM_DEBUG("disabling vblank on crtc %u\n", pipe);
-		vblank_disable_and_save(dev, pipe);
-	}
-	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
-}
-
-/**
- * drm_vblank_cleanup - cleanup vblank support
- * @dev: DRM device
- *
- * This function cleans up any resources allocated in drm_vblank_init.
- */
-void drm_vblank_cleanup(struct drm_device *dev)
-{
-	unsigned int pipe;
-
-	/* Bail if the driver didn't call drm_vblank_init() */
-	if (dev->num_crtcs == 0)
-		return;
-
-	for (pipe = 0; pipe < dev->num_crtcs; pipe++) {
-		struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
-
-		WARN_ON(READ_ONCE(vblank->enabled) &&
-			drm_core_check_feature(dev, DRIVER_MODESET));
-
-		del_timer_sync(&vblank->disable_timer);
-	}
-
-	kfree(dev->vblank);
-
-	dev->num_crtcs = 0;
-}
-EXPORT_SYMBOL(drm_vblank_cleanup);
-
-/**
- * drm_vblank_init - initialize vblank support
- * @dev: DRM device
- * @num_crtcs: number of CRTCs supported by @dev
- *
- * This function initializes vblank support for @num_crtcs display pipelines.
- *
- * Returns:
- * Zero on success or a negative error code on failure.
- */
-int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs)
-{
-	int ret = -ENOMEM;
-	unsigned int i;
-
-	spin_lock_init(&dev->vbl_lock);
-	spin_lock_init(&dev->vblank_time_lock);
-
-	dev->num_crtcs = num_crtcs;
-
-	dev->vblank = kcalloc(num_crtcs, sizeof(*dev->vblank), GFP_KERNEL);
-	if (!dev->vblank)
-		goto err;
-
-	for (i = 0; i < num_crtcs; i++) {
-		struct drm_vblank_crtc *vblank = &dev->vblank[i];
-
-		vblank->dev = dev;
-		vblank->pipe = i;
-		init_waitqueue_head(&vblank->queue);
-		setup_timer(&vblank->disable_timer, vblank_disable_fn,
-			    (unsigned long)vblank);
-		seqlock_init(&vblank->seqlock);
-	}
-
-	DRM_INFO("Supports vblank timestamp caching Rev 2 (21.10.2013).\n");
-
-	/* Driver specific high-precision vblank timestamping supported? */
-	if (dev->driver->get_vblank_timestamp)
-		DRM_INFO("Driver supports precise vblank timestamp query.\n");
-	else
-		DRM_INFO("No driver support for vblank timestamp query.\n");
-
-	/* Must have precise timestamping for reliable vblank instant disable */
-	if (dev->vblank_disable_immediate && !dev->driver->get_vblank_timestamp) {
-		dev->vblank_disable_immediate = false;
-		DRM_INFO("Setting vblank_disable_immediate to false because "
-			 "get_vblank_timestamp == NULL\n");
-	}
-
-	return 0;
-
-err:
-	dev->num_crtcs = 0;
-	return ret;
-}
-EXPORT_SYMBOL(drm_vblank_init);
+#include "drm_internal.h"
 
 /**
  * drm_irq_install - install IRQ handler
@@ -571,7 +176,7 @@ int drm_irq_uninstall(struct drm_device *dev)
 
 			WARN_ON(drm_core_check_feature(dev, DRIVER_MODESET));
 
-			vblank_disable_and_save(dev, i);
+			drm_vblank_disable_and_save(dev, i);
 			wake_up(&vblank->queue);
 		}
 		spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
@@ -634,1187 +239,3 @@ int drm_legacy_irq_control(struct drm_device *dev, void *data,
 		return -EINVAL;
 	}
 }
-
-/**
- * drm_calc_timestamping_constants - calculate vblank timestamp constants
- * @crtc: drm_crtc whose timestamp constants should be updated.
- * @mode: display mode containing the scanout timings
- *
- * Calculate and store various constants which are later
- * needed by vblank and swap-completion timestamping, e.g,
- * by drm_calc_vbltimestamp_from_scanoutpos(). They are
- * derived from CRTC's true scanout timing, so they take
- * things like panel scaling or other adjustments into account.
- */
-void drm_calc_timestamping_constants(struct drm_crtc *crtc,
-				     const struct drm_display_mode *mode)
-{
-	struct drm_device *dev = crtc->dev;
-	unsigned int pipe = drm_crtc_index(crtc);
-	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
-	int linedur_ns = 0, framedur_ns = 0;
-	int dotclock = mode->crtc_clock;
-
-	if (!dev->num_crtcs)
-		return;
-
-	if (WARN_ON(pipe >= dev->num_crtcs))
-		return;
-
-	/* Valid dotclock? */
-	if (dotclock > 0) {
-		int frame_size = mode->crtc_htotal * mode->crtc_vtotal;
-
-		/*
-		 * Convert scanline length in pixels and video
-		 * dot clock to line duration and frame duration
-		 * in nanoseconds:
-		 */
-		linedur_ns  = div_u64((u64) mode->crtc_htotal * 1000000, dotclock);
-		framedur_ns = div_u64((u64) frame_size * 1000000, dotclock);
-
-		/*
-		 * Fields of interlaced scanout modes are only half a frame duration.
-		 */
-		if (mode->flags & DRM_MODE_FLAG_INTERLACE)
-			framedur_ns /= 2;
-	} else
-		DRM_ERROR("crtc %u: Can't calculate constants, dotclock = 0!\n",
-			  crtc->base.id);
-
-	vblank->linedur_ns  = linedur_ns;
-	vblank->framedur_ns = framedur_ns;
-	vblank->hwmode = *mode;
-
-	DRM_DEBUG("crtc %u: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
-		  crtc->base.id, mode->crtc_htotal,
-		  mode->crtc_vtotal, mode->crtc_vdisplay);
-	DRM_DEBUG("crtc %u: clock %d kHz framedur %d linedur %d\n",
-		  crtc->base.id, dotclock, framedur_ns, linedur_ns);
-}
-EXPORT_SYMBOL(drm_calc_timestamping_constants);
-
-/**
- * drm_calc_vbltimestamp_from_scanoutpos - precise vblank timestamp helper
- * @dev: DRM device
- * @pipe: index of CRTC whose vblank timestamp to retrieve
- * @max_error: Desired maximum allowable error in timestamps (nanosecs)
- *             On return contains true maximum error of timestamp
- * @vblank_time: Pointer to struct timeval which should receive the timestamp
- * @in_vblank_irq:
- *     True when called from drm_crtc_handle_vblank().  Some drivers
- *     need to apply some workarounds for gpu-specific vblank irq quirks
- *     if flag is set.
- *
- * Implements calculation of exact vblank timestamps from given drm_display_mode
- * timings and current video scanout position of a CRTC. This can be called from
- * within get_vblank_timestamp() implementation of a kms driver to implement the
- * actual timestamping.
- *
- * Should return timestamps conforming to the OML_sync_control OpenML
- * extension specification. The timestamp corresponds to the end of
- * the vblank interval, aka start of scanout of topmost-leftmost display
- * pixel in the following video frame.
- *
- * Requires support for optional dev->driver->get_scanout_position()
- * in kms driver, plus a bit of setup code to provide a drm_display_mode
- * that corresponds to the true scanout timing.
- *
- * The current implementation only handles standard video modes. It
- * returns as no operation if a doublescan or interlaced video mode is
- * active. Higher level code is expected to handle this.
- *
- * This function can be used to implement the &drm_driver.get_vblank_timestamp
- * directly, if the driver implements the &drm_driver.get_scanout_position hook.
- *
- * Note that atomic drivers must call drm_calc_timestamping_constants() before
- * enabling a CRTC. The atomic helpers already take care of that in
- * drm_atomic_helper_update_legacy_modeset_state().
- *
- * Returns:
- *
- * Returns true on success, and false on failure, i.e. when no accurate
- * timestamp could be acquired.
- */
-bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
-					   unsigned int pipe,
-					   int *max_error,
-					   struct timeval *vblank_time,
-					   bool in_vblank_irq)
-{
-	struct timeval tv_etime;
-	ktime_t stime, etime;
-	bool vbl_status;
-	struct drm_crtc *crtc;
-	const struct drm_display_mode *mode;
-	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
-	int vpos, hpos, i;
-	int delta_ns, duration_ns;
-
-	if (!drm_core_check_feature(dev, DRIVER_MODESET))
-		return false;
-
-	crtc = drm_crtc_from_index(dev, pipe);
-
-	if (pipe >= dev->num_crtcs || !crtc) {
-		DRM_ERROR("Invalid crtc %u\n", pipe);
-		return false;
-	}
-
-	/* Scanout position query not supported? Should not happen. */
-	if (!dev->driver->get_scanout_position) {
-		DRM_ERROR("Called from driver w/o get_scanout_position()!?\n");
-		return false;
-	}
-
-	if (drm_drv_uses_atomic_modeset(dev))
-		mode = &vblank->hwmode;
-	else
-		mode = &crtc->hwmode;
-
-	/* If mode timing undefined, just return as no-op:
-	 * Happens during initial modesetting of a crtc.
-	 */
-	if (mode->crtc_clock == 0) {
-		DRM_DEBUG("crtc %u: Noop due to uninitialized mode.\n", pipe);
-		WARN_ON_ONCE(drm_drv_uses_atomic_modeset(dev));
-
-		return false;
-	}
-
-	/* Get current scanout position with system timestamp.
-	 * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times
-	 * if single query takes longer than max_error nanoseconds.
-	 *
-	 * This guarantees a tight bound on maximum error if
-	 * code gets preempted or delayed for some reason.
-	 */
-	for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) {
-		/*
-		 * Get vertical and horizontal scanout position vpos, hpos,
-		 * and bounding timestamps stime, etime, pre/post query.
-		 */
-		vbl_status = dev->driver->get_scanout_position(dev, pipe,
-							       in_vblank_irq,
-							       &vpos, &hpos,
-							       &stime, &etime,
-							       mode);
-
-		/* Return as no-op if scanout query unsupported or failed. */
-		if (!vbl_status) {
-			DRM_DEBUG("crtc %u : scanoutpos query failed.\n",
-				  pipe);
-			return false;
-		}
-
-		/* Compute uncertainty in timestamp of scanout position query. */
-		duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime);
-
-		/* Accept result with <  max_error nsecs timing uncertainty. */
-		if (duration_ns <= *max_error)
-			break;
-	}
-
-	/* Noisy system timing? */
-	if (i == DRM_TIMESTAMP_MAXRETRIES) {
-		DRM_DEBUG("crtc %u: Noisy timestamp %d us > %d us [%d reps].\n",
-			  pipe, duration_ns/1000, *max_error/1000, i);
-	}
-
-	/* Return upper bound of timestamp precision error. */
-	*max_error = duration_ns;
-
-	/* Convert scanout position into elapsed time at raw_time query
-	 * since start of scanout at first display scanline. delta_ns
-	 * can be negative if start of scanout hasn't happened yet.
-	 */
-	delta_ns = div_s64(1000000LL * (vpos * mode->crtc_htotal + hpos),
-			   mode->crtc_clock);
-
-	if (!drm_timestamp_monotonic)
-		etime = ktime_mono_to_real(etime);
-
-	/* save this only for debugging purposes */
-	tv_etime = ktime_to_timeval(etime);
-	/* Subtract time delta from raw timestamp to get final
-	 * vblank_time timestamp for end of vblank.
-	 */
-	etime = ktime_sub_ns(etime, delta_ns);
-	*vblank_time = ktime_to_timeval(etime);
-
-	DRM_DEBUG_VBL("crtc %u : v p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n",
-		      pipe, hpos, vpos,
-		      (long)tv_etime.tv_sec, (long)tv_etime.tv_usec,
-		      (long)vblank_time->tv_sec, (long)vblank_time->tv_usec,
-		      duration_ns/1000, i);
-
-	return true;
-}
-EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);
-
-static struct timeval get_drm_timestamp(void)
-{
-	ktime_t now;
-
-	now = drm_timestamp_monotonic ? ktime_get() : ktime_get_real();
-	return ktime_to_timeval(now);
-}
-
-/**
- * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent
- *                             vblank interval
- * @dev: DRM device
- * @pipe: index of CRTC whose vblank timestamp to retrieve
- * @tvblank: Pointer to target struct timeval which should receive the timestamp
- * @in_vblank_irq:
- *     True when called from drm_crtc_handle_vblank().  Some drivers
- *     need to apply some workarounds for gpu-specific vblank irq quirks
- *     if flag is set.
- *
- * Fetches the system timestamp corresponding to the time of the most recent
- * vblank interval on specified CRTC. May call into kms-driver to
- * compute the timestamp with a high-precision GPU specific method.
- *
- * Returns zero if timestamp originates from uncorrected do_gettimeofday()
- * call, i.e., it isn't very precisely locked to the true vblank.
- *
- * Returns:
- * True if timestamp is considered to be very precise, false otherwise.
- */
-static bool
-drm_get_last_vbltimestamp(struct drm_device *dev, unsigned int pipe,
-			  struct timeval *tvblank, bool in_vblank_irq)
-{
-	bool ret = false;
-
-	/* Define requested maximum error on timestamps (nanoseconds). */
-	int max_error = (int) drm_timestamp_precision * 1000;
-
-	/* Query driver if possible and precision timestamping enabled. */
-	if (dev->driver->get_vblank_timestamp && (max_error > 0))
-		ret = dev->driver->get_vblank_timestamp(dev, pipe, &max_error,
-							tvblank, in_vblank_irq);
-
-	/* GPU high precision timestamp query unsupported or failed.
-	 * Return current monotonic/gettimeofday timestamp as best estimate.
-	 */
-	if (!ret)
-		*tvblank = get_drm_timestamp();
-
-	return ret;
-}
-
-/**
- * drm_crtc_vblank_count - retrieve "cooked" vblank counter value
- * @crtc: which counter to retrieve
- *
- * Fetches the "cooked" vblank count value that represents the number of
- * vblank events since the system was booted, including lost events due to
- * modesetting activity.
- *
- * Returns:
- * The software vblank counter.
- */
-u32 drm_crtc_vblank_count(struct drm_crtc *crtc)
-{
-	return drm_vblank_count(crtc->dev, drm_crtc_index(crtc));
-}
-EXPORT_SYMBOL(drm_crtc_vblank_count);
-
-/**
- * drm_vblank_count_and_time - retrieve "cooked" vblank counter value and the
- *     system timestamp corresponding to that vblank counter value.
- * @dev: DRM device
- * @pipe: index of CRTC whose counter to retrieve
- * @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
- *
- * Fetches the "cooked" vblank count value that represents the number of
- * vblank events since the system was booted, including lost events due to
- * modesetting activity. Returns corresponding system timestamp of the time
- * of the vblank interval that corresponds to the current vblank counter value.
- *
- * This is the legacy version of drm_crtc_vblank_count_and_time().
- */
-static u32 drm_vblank_count_and_time(struct drm_device *dev, unsigned int pipe,
-				     struct timeval *vblanktime)
-{
-	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
-	u32 vblank_count;
-	unsigned int seq;
-
-	if (WARN_ON(pipe >= dev->num_crtcs)) {
-		*vblanktime = (struct timeval) { 0 };
-		return 0;
-	}
-
-	do {
-		seq = read_seqbegin(&vblank->seqlock);
-		vblank_count = vblank->count;
-		*vblanktime = vblank->time;
-	} while (read_seqretry(&vblank->seqlock, seq));
-
-	return vblank_count;
-}
-
-/**
- * drm_crtc_vblank_count_and_time - retrieve "cooked" vblank counter value
- *     and the system timestamp corresponding to that vblank counter value
- * @crtc: which counter to retrieve
- * @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
- *
- * Fetches the "cooked" vblank count value that represents the number of
- * vblank events since the system was booted, including lost events due to
- * modesetting activity. Returns corresponding system timestamp of the time
- * of the vblank interval that corresponds to the current vblank counter value.
- */
-u32 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
-				   struct timeval *vblanktime)
-{
-	return drm_vblank_count_and_time(crtc->dev, drm_crtc_index(crtc),
-					 vblanktime);
-}
-EXPORT_SYMBOL(drm_crtc_vblank_count_and_time);
-
-static void send_vblank_event(struct drm_device *dev,
-		struct drm_pending_vblank_event *e,
-		unsigned long seq, struct timeval *now)
-{
-	e->event.sequence = seq;
-	e->event.tv_sec = now->tv_sec;
-	e->event.tv_usec = now->tv_usec;
-
-	trace_drm_vblank_event_delivered(e->base.file_priv, e->pipe,
-					 e->event.sequence);
-
-	drm_send_event_locked(dev, &e->base);
-}
-
-/**
- * drm_crtc_arm_vblank_event - arm vblank event after pageflip
- * @crtc: the source CRTC of the vblank event
- * @e: the event to send
- *
- * A lot of drivers need to generate vblank events for the very next vblank
- * interrupt. For example when the page flip interrupt happens when the page
- * flip gets armed, but not when it actually executes within the next vblank
- * period. This helper function implements exactly the required vblank arming
- * behaviour.
- *
- * NOTE: Drivers using this to send out the &drm_crtc_state.event as part of an
- * atomic commit must ensure that the next vblank happens at exactly the same
- * time as the atomic commit is committed to the hardware. This function itself
- * does **not** protect again the next vblank interrupt racing with either this
- * function call or the atomic commit operation. A possible sequence could be:
- *
- * 1. Driver commits new hardware state into vblank-synchronized registers.
- * 2. A vblank happens, committing the hardware state. Also the corresponding
- *    vblank interrupt is fired off and fully processed by the interrupt
- *    handler.
- * 3. The atomic commit operation proceeds to call drm_crtc_arm_vblank_event().
- * 4. The event is only send out for the next vblank, which is wrong.
- *
- * An equivalent race can happen when the driver calls
- * drm_crtc_arm_vblank_event() before writing out the new hardware state.
- *
- * The only way to make this work safely is to prevent the vblank from firing
- * (and the hardware from committing anything else) until the entire atomic
- * commit sequence has run to completion. If the hardware does not have such a
- * feature (e.g. using a "go" bit), then it is unsafe to use this functions.
- * Instead drivers need to manually send out the event from their interrupt
- * handler by calling drm_crtc_send_vblank_event() and make sure that there's no
- * possible race with the hardware committing the atomic update.
- *
- * Caller must hold event lock. Caller must also hold a vblank reference for
- * the event @e, which will be dropped when the next vblank arrives.
- */
-void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
-			       struct drm_pending_vblank_event *e)
-{
-	struct drm_device *dev = crtc->dev;
-	unsigned int pipe = drm_crtc_index(crtc);
-
-	assert_spin_locked(&dev->event_lock);
-
-	e->pipe = pipe;
-	e->event.sequence = drm_vblank_count(dev, pipe);
-	e->event.crtc_id = crtc->base.id;
-	list_add_tail(&e->base.link, &dev->vblank_event_list);
-}
-EXPORT_SYMBOL(drm_crtc_arm_vblank_event);
-
-/**
- * drm_crtc_send_vblank_event - helper to send vblank event after pageflip
- * @crtc: the source CRTC of the vblank event
- * @e: the event to send
- *
- * Updates sequence # and timestamp on event for the most recently processed
- * vblank, and sends it to userspace.  Caller must hold event lock.
- *
- * See drm_crtc_arm_vblank_event() for a helper which can be used in certain
- * situation, especially to send out events for atomic commit operations.
- */
-void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
-				struct drm_pending_vblank_event *e)
-{
-	struct drm_device *dev = crtc->dev;
-	unsigned int seq, pipe = drm_crtc_index(crtc);
-	struct timeval now;
-
-	if (dev->num_crtcs > 0) {
-		seq = drm_vblank_count_and_time(dev, pipe, &now);
-	} else {
-		seq = 0;
-
-		now = get_drm_timestamp();
-	}
-	e->pipe = pipe;
-	e->event.crtc_id = crtc->base.id;
-	send_vblank_event(dev, e, seq, &now);
-}
-EXPORT_SYMBOL(drm_crtc_send_vblank_event);
-
-static int __enable_vblank(struct drm_device *dev, unsigned int pipe)
-{
-	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
-		struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
-
-		if (crtc->funcs->enable_vblank)
-			return crtc->funcs->enable_vblank(crtc);
-	}
-
-	return dev->driver->enable_vblank(dev, pipe);
-}
-
-/**
- * drm_vblank_enable - enable the vblank interrupt on a CRTC
- * @dev: DRM device
- * @pipe: CRTC index
- *
- * Returns:
- * Zero on success or a negative error code on failure.
- */
-static int drm_vblank_enable(struct drm_device *dev, unsigned int pipe)
-{
-	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
-	int ret = 0;
-
-	assert_spin_locked(&dev->vbl_lock);
-
-	spin_lock(&dev->vblank_time_lock);
-
-	if (!vblank->enabled) {
-		/*
-		 * Enable vblank irqs under vblank_time_lock protection.
-		 * All vblank count & timestamp updates are held off
-		 * until we are done reinitializing master counter and
-		 * timestamps. Filtercode in drm_handle_vblank() will
-		 * prevent double-accounting of same vblank interval.
-		 */
-		ret = __enable_vblank(dev, pipe);
-		DRM_DEBUG("enabling vblank on crtc %u, ret: %d\n", pipe, ret);
-		if (ret) {
-			atomic_dec(&vblank->refcount);
-		} else {
-			drm_update_vblank_count(dev, pipe, 0);
-			/* drm_update_vblank_count() includes a wmb so we just
-			 * need to ensure that the compiler emits the write
-			 * to mark the vblank as enabled after the call
-			 * to drm_update_vblank_count().
-			 */
-			WRITE_ONCE(vblank->enabled, true);
-		}
-	}
-
-	spin_unlock(&dev->vblank_time_lock);
-
-	return ret;
-}
-
-/**
- * drm_vblank_get - get a reference count on vblank events
- * @dev: DRM device
- * @pipe: index of CRTC to own
- *
- * Acquire a reference count on vblank events to avoid having them disabled
- * while in use.
- *
- * This is the legacy version of drm_crtc_vblank_get().
- *
- * Returns:
- * Zero on success or a negative error code on failure.
- */
-static int drm_vblank_get(struct drm_device *dev, unsigned int pipe)
-{
-	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
-	unsigned long irqflags;
-	int ret = 0;
-
-	if (!dev->num_crtcs)
-		return -EINVAL;
-
-	if (WARN_ON(pipe >= dev->num_crtcs))
-		return -EINVAL;
-
-	spin_lock_irqsave(&dev->vbl_lock, irqflags);
-	/* Going from 0->1 means we have to enable interrupts again */
-	if (atomic_add_return(1, &vblank->refcount) == 1) {
-		ret = drm_vblank_enable(dev, pipe);
-	} else {
-		if (!vblank->enabled) {
-			atomic_dec(&vblank->refcount);
-			ret = -EINVAL;
-		}
-	}
-	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
-
-	return ret;
-}
-
-/**
- * drm_crtc_vblank_get - get a reference count on vblank events
- * @crtc: which CRTC to own
- *
- * Acquire a reference count on vblank events to avoid having them disabled
- * while in use.
- *
- * Returns:
- * Zero on success or a negative error code on failure.
- */
-int drm_crtc_vblank_get(struct drm_crtc *crtc)
-{
-	return drm_vblank_get(crtc->dev, drm_crtc_index(crtc));
-}
-EXPORT_SYMBOL(drm_crtc_vblank_get);
-
-/**
- * drm_vblank_put - release ownership of vblank events
- * @dev: DRM device
- * @pipe: index of CRTC to release
- *
- * Release ownership of a given vblank counter, turning off interrupts
- * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
- *
- * This is the legacy version of drm_crtc_vblank_put().
- */
-static void drm_vblank_put(struct drm_device *dev, unsigned int pipe)
-{
-	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
-
-	if (WARN_ON(pipe >= dev->num_crtcs))
-		return;
-
-	if (WARN_ON(atomic_read(&vblank->refcount) == 0))
-		return;
-
-	/* Last user schedules interrupt disable */
-	if (atomic_dec_and_test(&vblank->refcount)) {
-		if (drm_vblank_offdelay == 0)
-			return;
-		else if (drm_vblank_offdelay < 0)
-			vblank_disable_fn((unsigned long)vblank);
-		else if (!dev->vblank_disable_immediate)
-			mod_timer(&vblank->disable_timer,
-				  jiffies + ((drm_vblank_offdelay * HZ)/1000));
-	}
-}
-
-/**
- * drm_crtc_vblank_put - give up ownership of vblank events
- * @crtc: which counter to give up
- *
- * Release ownership of a given vblank counter, turning off interrupts
- * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
- */
-void drm_crtc_vblank_put(struct drm_crtc *crtc)
-{
-	drm_vblank_put(crtc->dev, drm_crtc_index(crtc));
-}
-EXPORT_SYMBOL(drm_crtc_vblank_put);
-
-/**
- * drm_wait_one_vblank - wait for one vblank
- * @dev: DRM device
- * @pipe: CRTC index
- *
- * This waits for one vblank to pass on @pipe, using the irq driver interfaces.
- * It is a failure to call this when the vblank irq for @pipe is disabled, e.g.
- * due to lack of driver support or because the crtc is off.
- */
-void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe)
-{
-	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
-	int ret;
-	u32 last;
-
-	if (WARN_ON(pipe >= dev->num_crtcs))
-		return;
-
-	ret = drm_vblank_get(dev, pipe);
-	if (WARN(ret, "vblank not available on crtc %i, ret=%i\n", pipe, ret))
-		return;
-
-	last = drm_vblank_count(dev, pipe);
-
-	ret = wait_event_timeout(vblank->queue,
-				 last != drm_vblank_count(dev, pipe),
-				 msecs_to_jiffies(100));
-
-	WARN(ret == 0, "vblank wait timed out on crtc %i\n", pipe);
-
-	drm_vblank_put(dev, pipe);
-}
-EXPORT_SYMBOL(drm_wait_one_vblank);
-
-/**
- * drm_crtc_wait_one_vblank - wait for one vblank
- * @crtc: DRM crtc
- *
- * This waits for one vblank to pass on @crtc, using the irq driver interfaces.
- * It is a failure to call this when the vblank irq for @crtc is disabled, e.g.
- * due to lack of driver support or because the crtc is off.
- */
-void drm_crtc_wait_one_vblank(struct drm_crtc *crtc)
-{
-	drm_wait_one_vblank(crtc->dev, drm_crtc_index(crtc));
-}
-EXPORT_SYMBOL(drm_crtc_wait_one_vblank);
-
-/**
- * drm_crtc_vblank_off - disable vblank events on a CRTC
- * @crtc: CRTC in question
- *
- * Drivers can use this function to shut down the vblank interrupt handling when
- * disabling a crtc. This function ensures that the latest vblank frame count is
- * stored so that drm_vblank_on can restore it again.
- *
- * Drivers must use this function when the hardware vblank counter can get
- * reset, e.g. when suspending.
- */
-void drm_crtc_vblank_off(struct drm_crtc *crtc)
-{
-	struct drm_device *dev = crtc->dev;
-	unsigned int pipe = drm_crtc_index(crtc);
-	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
-	struct drm_pending_vblank_event *e, *t;
-	struct timeval now;
-	unsigned long irqflags;
-	unsigned int seq;
-
-	if (WARN_ON(pipe >= dev->num_crtcs))
-		return;
-
-	spin_lock_irqsave(&dev->event_lock, irqflags);
-
-	spin_lock(&dev->vbl_lock);
-	DRM_DEBUG_VBL("crtc %d, vblank enabled %d, inmodeset %d\n",
-		      pipe, vblank->enabled, vblank->inmodeset);
-
-	/* Avoid redundant vblank disables without previous
-	 * drm_crtc_vblank_on(). */
-	if (drm_core_check_feature(dev, DRIVER_ATOMIC) || !vblank->inmodeset)
-		vblank_disable_and_save(dev, pipe);
-
-	wake_up(&vblank->queue);
-
-	/*
-	 * Prevent subsequent drm_vblank_get() from re-enabling
-	 * the vblank interrupt by bumping the refcount.
-	 */
-	if (!vblank->inmodeset) {
-		atomic_inc(&vblank->refcount);
-		vblank->inmodeset = 1;
-	}
-	spin_unlock(&dev->vbl_lock);
-
-	/* Send any queued vblank events, lest the natives grow disquiet */
-	seq = drm_vblank_count_and_time(dev, pipe, &now);
-
-	list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
-		if (e->pipe != pipe)
-			continue;
-		DRM_DEBUG("Sending premature vblank event on disable: "
-			  "wanted %u, current %u\n",
-			  e->event.sequence, seq);
-		list_del(&e->base.link);
-		drm_vblank_put(dev, pipe);
-		send_vblank_event(dev, e, seq, &now);
-	}
-	spin_unlock_irqrestore(&dev->event_lock, irqflags);
-
-	/* Will be reset by the modeset helpers when re-enabling the crtc by
-	 * calling drm_calc_timestamping_constants(). */
-	vblank->hwmode.crtc_clock = 0;
-}
-EXPORT_SYMBOL(drm_crtc_vblank_off);
-
-/**
- * drm_crtc_vblank_reset - reset vblank state to off on a CRTC
- * @crtc: CRTC in question
- *
- * Drivers can use this function to reset the vblank state to off at load time.
- * Drivers should use this together with the drm_crtc_vblank_off() and
- * drm_crtc_vblank_on() functions. The difference compared to
- * drm_crtc_vblank_off() is that this function doesn't save the vblank counter
- * and hence doesn't need to call any driver hooks.
- */
-void drm_crtc_vblank_reset(struct drm_crtc *crtc)
-{
-	struct drm_device *dev = crtc->dev;
-	unsigned long irqflags;
-	unsigned int pipe = drm_crtc_index(crtc);
-	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
-
-	spin_lock_irqsave(&dev->vbl_lock, irqflags);
-	/*
-	 * Prevent subsequent drm_vblank_get() from enabling the vblank
-	 * interrupt by bumping the refcount.
-	 */
-	if (!vblank->inmodeset) {
-		atomic_inc(&vblank->refcount);
-		vblank->inmodeset = 1;
-	}
-	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
-
-	WARN_ON(!list_empty(&dev->vblank_event_list));
-}
-EXPORT_SYMBOL(drm_crtc_vblank_reset);
-
-/**
- * drm_crtc_vblank_on - enable vblank events on a CRTC
- * @crtc: CRTC in question
- *
- * This functions restores the vblank interrupt state captured with
- * drm_crtc_vblank_off() again. Note that calls to drm_crtc_vblank_on() and
- * drm_crtc_vblank_off() can be unbalanced and so can also be unconditionally called
- * in driver load code to reflect the current hardware state of the crtc.
- */
-void drm_crtc_vblank_on(struct drm_crtc *crtc)
-{
-	struct drm_device *dev = crtc->dev;
-	unsigned int pipe = drm_crtc_index(crtc);
-	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
-	unsigned long irqflags;
-
-	if (WARN_ON(pipe >= dev->num_crtcs))
-		return;
-
-	spin_lock_irqsave(&dev->vbl_lock, irqflags);
-	DRM_DEBUG_VBL("crtc %d, vblank enabled %d, inmodeset %d\n",
-		      pipe, vblank->enabled, vblank->inmodeset);
-
-	/* Drop our private "prevent drm_vblank_get" refcount */
-	if (vblank->inmodeset) {
-		atomic_dec(&vblank->refcount);
-		vblank->inmodeset = 0;
-	}
-
-	drm_reset_vblank_timestamp(dev, pipe);
-
-	/*
-	 * re-enable interrupts if there are users left, or the
-	 * user wishes vblank interrupts to be enabled all the time.
-	 */
-	if (atomic_read(&vblank->refcount) != 0 || drm_vblank_offdelay == 0)
-		WARN_ON(drm_vblank_enable(dev, pipe));
-	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
-}
-EXPORT_SYMBOL(drm_crtc_vblank_on);
-
-static void drm_legacy_vblank_pre_modeset(struct drm_device *dev,
-					  unsigned int pipe)
-{
-	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
-
-	/* vblank is not initialized (IRQ not installed ?), or has been freed */
-	if (!dev->num_crtcs)
-		return;
-
-	if (WARN_ON(pipe >= dev->num_crtcs))
-		return;
-
-	/*
-	 * To avoid all the problems that might happen if interrupts
-	 * were enabled/disabled around or between these calls, we just
-	 * have the kernel take a reference on the CRTC (just once though
-	 * to avoid corrupting the count if multiple, mismatch calls occur),
-	 * so that interrupts remain enabled in the interim.
-	 */
-	if (!vblank->inmodeset) {
-		vblank->inmodeset = 0x1;
-		if (drm_vblank_get(dev, pipe) == 0)
-			vblank->inmodeset |= 0x2;
-	}
-}
-
-static void drm_legacy_vblank_post_modeset(struct drm_device *dev,
-					   unsigned int pipe)
-{
-	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
-	unsigned long irqflags;
-
-	/* vblank is not initialized (IRQ not installed ?), or has been freed */
-	if (!dev->num_crtcs)
-		return;
-
-	if (WARN_ON(pipe >= dev->num_crtcs))
-		return;
-
-	if (vblank->inmodeset) {
-		spin_lock_irqsave(&dev->vbl_lock, irqflags);
-		drm_reset_vblank_timestamp(dev, pipe);
-		spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
-
-		if (vblank->inmodeset & 0x2)
-			drm_vblank_put(dev, pipe);
-
-		vblank->inmodeset = 0;
-	}
-}
-
-int drm_legacy_modeset_ctl(struct drm_device *dev, void *data,
-			   struct drm_file *file_priv)
-{
-	struct drm_modeset_ctl *modeset = data;
-	unsigned int pipe;
-
-	/* If drm_vblank_init() hasn't been called yet, just no-op */
-	if (!dev->num_crtcs)
-		return 0;
-
-	/* KMS drivers handle this internally */
-	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
-		return 0;
-
-	pipe = modeset->crtc;
-	if (pipe >= dev->num_crtcs)
-		return -EINVAL;
-
-	switch (modeset->cmd) {
-	case _DRM_PRE_MODESET:
-		drm_legacy_vblank_pre_modeset(dev, pipe);
-		break;
-	case _DRM_POST_MODESET:
-		drm_legacy_vblank_post_modeset(dev, pipe);
-		break;
-	default:
-		return -EINVAL;
-	}
-
-	return 0;
-}
-
-static inline bool vblank_passed(u32 seq, u32 ref)
-{
-	return (seq - ref) <= (1 << 23);
-}
-
-static int drm_queue_vblank_event(struct drm_device *dev, unsigned int pipe,
-				  union drm_wait_vblank *vblwait,
-				  struct drm_file *file_priv)
-{
-	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
-	struct drm_pending_vblank_event *e;
-	struct timeval now;
-	unsigned long flags;
-	unsigned int seq;
-	int ret;
-
-	e = kzalloc(sizeof(*e), GFP_KERNEL);
-	if (e == NULL) {
-		ret = -ENOMEM;
-		goto err_put;
-	}
-
-	e->pipe = pipe;
-	e->event.base.type = DRM_EVENT_VBLANK;
-	e->event.base.length = sizeof(e->event);
-	e->event.user_data = vblwait->request.signal;
-
-	spin_lock_irqsave(&dev->event_lock, flags);
-
-	/*
-	 * drm_crtc_vblank_off() might have been called after we called
-	 * drm_vblank_get(). drm_crtc_vblank_off() holds event_lock around the
-	 * vblank disable, so no need for further locking.  The reference from
-	 * drm_vblank_get() protects against vblank disable from another source.
-	 */
-	if (!READ_ONCE(vblank->enabled)) {
-		ret = -EINVAL;
-		goto err_unlock;
-	}
-
-	ret = drm_event_reserve_init_locked(dev, file_priv, &e->base,
-					    &e->event.base);
-
-	if (ret)
-		goto err_unlock;
-
-	seq = drm_vblank_count_and_time(dev, pipe, &now);
-
-	DRM_DEBUG("event on vblank count %u, current %u, crtc %u\n",
-		  vblwait->request.sequence, seq, pipe);
-
-	trace_drm_vblank_event_queued(file_priv, pipe,
-				      vblwait->request.sequence);
-
-	e->event.sequence = vblwait->request.sequence;
-	if (vblank_passed(seq, vblwait->request.sequence)) {
-		drm_vblank_put(dev, pipe);
-		send_vblank_event(dev, e, seq, &now);
-		vblwait->reply.sequence = seq;
-	} else {
-		/* drm_handle_vblank_events will call drm_vblank_put */
-		list_add_tail(&e->base.link, &dev->vblank_event_list);
-		vblwait->reply.sequence = vblwait->request.sequence;
-	}
-
-	spin_unlock_irqrestore(&dev->event_lock, flags);
-
-	return 0;
-
-err_unlock:
-	spin_unlock_irqrestore(&dev->event_lock, flags);
-	kfree(e);
-err_put:
-	drm_vblank_put(dev, pipe);
-	return ret;
-}
-
-static bool drm_wait_vblank_is_query(union drm_wait_vblank *vblwait)
-{
-	if (vblwait->request.sequence)
-		return false;
-
-	return _DRM_VBLANK_RELATIVE ==
-		(vblwait->request.type & (_DRM_VBLANK_TYPES_MASK |
-					  _DRM_VBLANK_EVENT |
-					  _DRM_VBLANK_NEXTONMISS));
-}
-
-/*
- * Wait for VBLANK.
- *
- * \param inode device inode.
- * \param file_priv DRM file private.
- * \param cmd command.
- * \param data user argument, pointing to a drm_wait_vblank structure.
- * \return zero on success or a negative number on failure.
- *
- * This function enables the vblank interrupt on the pipe requested, then
- * sleeps waiting for the requested sequence number to occur, and drops
- * the vblank interrupt refcount afterwards. (vblank IRQ disable follows that
- * after a timeout with no further vblank waits scheduled).
- */
-int drm_wait_vblank(struct drm_device *dev, void *data,
-		    struct drm_file *file_priv)
-{
-	struct drm_vblank_crtc *vblank;
-	union drm_wait_vblank *vblwait = data;
-	int ret;
-	unsigned int flags, seq, pipe, high_pipe;
-
-	if (!dev->irq_enabled)
-		return -EINVAL;
-
-	if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
-		return -EINVAL;
-
-	if (vblwait->request.type &
-	    ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
-	      _DRM_VBLANK_HIGH_CRTC_MASK)) {
-		DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
-			  vblwait->request.type,
-			  (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
-			   _DRM_VBLANK_HIGH_CRTC_MASK));
-		return -EINVAL;
-	}
-
-	flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
-	high_pipe = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK);
-	if (high_pipe)
-		pipe = high_pipe >> _DRM_VBLANK_HIGH_CRTC_SHIFT;
-	else
-		pipe = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
-	if (pipe >= dev->num_crtcs)
-		return -EINVAL;
-
-	vblank = &dev->vblank[pipe];
-
-	/* If the counter is currently enabled and accurate, short-circuit
-	 * queries to return the cached timestamp of the last vblank.
-	 */
-	if (dev->vblank_disable_immediate &&
-	    drm_wait_vblank_is_query(vblwait) &&
-	    READ_ONCE(vblank->enabled)) {
-		struct timeval now;
-
-		vblwait->reply.sequence =
-			drm_vblank_count_and_time(dev, pipe, &now);
-		vblwait->reply.tval_sec = now.tv_sec;
-		vblwait->reply.tval_usec = now.tv_usec;
-		return 0;
-	}
-
-	ret = drm_vblank_get(dev, pipe);
-	if (ret) {
-		DRM_DEBUG("crtc %d failed to acquire vblank counter, %d\n", pipe, ret);
-		return ret;
-	}
-	seq = drm_vblank_count(dev, pipe);
-
-	switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
-	case _DRM_VBLANK_RELATIVE:
-		vblwait->request.sequence += seq;
-		vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
-	case _DRM_VBLANK_ABSOLUTE:
-		break;
-	default:
-		ret = -EINVAL;
-		goto done;
-	}
-
-	if ((flags & _DRM_VBLANK_NEXTONMISS) &&
-	    vblank_passed(seq, vblwait->request.sequence))
-		vblwait->request.sequence = seq + 1;
-
-	if (flags & _DRM_VBLANK_EVENT) {
-		/* must hold on to the vblank ref until the event fires
-		 * drm_vblank_put will be called asynchronously
-		 */
-		return drm_queue_vblank_event(dev, pipe, vblwait, file_priv);
-	}
-
-	if (vblwait->request.sequence != seq) {
-		DRM_DEBUG("waiting on vblank count %u, crtc %u\n",
-			  vblwait->request.sequence, pipe);
-		DRM_WAIT_ON(ret, vblank->queue, 3 * HZ,
-			    vblank_passed(drm_vblank_count(dev, pipe),
-					  vblwait->request.sequence) ||
-			    !READ_ONCE(vblank->enabled));
-	}
-
-	if (ret != -EINTR) {
-		struct timeval now;
-
-		vblwait->reply.sequence = drm_vblank_count_and_time(dev, pipe, &now);
-		vblwait->reply.tval_sec = now.tv_sec;
-		vblwait->reply.tval_usec = now.tv_usec;
-
-		DRM_DEBUG("crtc %d returning %u to client\n",
-			  pipe, vblwait->reply.sequence);
-	} else {
-		DRM_DEBUG("crtc %d vblank wait interrupted by signal\n", pipe);
-	}
-
-done:
-	drm_vblank_put(dev, pipe);
-	return ret;
-}
-
-static void drm_handle_vblank_events(struct drm_device *dev, unsigned int pipe)
-{
-	struct drm_pending_vblank_event *e, *t;
-	struct timeval now;
-	unsigned int seq;
-
-	assert_spin_locked(&dev->event_lock);
-
-	seq = drm_vblank_count_and_time(dev, pipe, &now);
-
-	list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
-		if (e->pipe != pipe)
-			continue;
-		if (!vblank_passed(seq, e->event.sequence))
-			continue;
-
-		DRM_DEBUG("vblank event on %u, current %u\n",
-			  e->event.sequence, seq);
-
-		list_del(&e->base.link);
-		drm_vblank_put(dev, pipe);
-		send_vblank_event(dev, e, seq, &now);
-	}
-
-	trace_drm_vblank_event(pipe, seq);
-}
-
-/**
- * drm_handle_vblank - handle a vblank event
- * @dev: DRM device
- * @pipe: index of CRTC where this event occurred
- *
- * Drivers should call this routine in their vblank interrupt handlers to
- * update the vblank counter and send any signals that may be pending.
- *
- * This is the legacy version of drm_crtc_handle_vblank().
- */
-bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe)
-{
-	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
-	unsigned long irqflags;
-	bool disable_irq;
-
-	if (WARN_ON_ONCE(!dev->num_crtcs))
-		return false;
-
-	if (WARN_ON(pipe >= dev->num_crtcs))
-		return false;
-
-	spin_lock_irqsave(&dev->event_lock, irqflags);
-
-	/* Need timestamp lock to prevent concurrent execution with
-	 * vblank enable/disable, as this would cause inconsistent
-	 * or corrupted timestamps and vblank counts.
-	 */
-	spin_lock(&dev->vblank_time_lock);
-
-	/* Vblank irq handling disabled. Nothing to do. */
-	if (!vblank->enabled) {
-		spin_unlock(&dev->vblank_time_lock);
-		spin_unlock_irqrestore(&dev->event_lock, irqflags);
-		return false;
-	}
-
-	drm_update_vblank_count(dev, pipe, true);
-
-	spin_unlock(&dev->vblank_time_lock);
-
-	wake_up(&vblank->queue);
-
-	/* With instant-off, we defer disabling the interrupt until after
-	 * we finish processing the following vblank after all events have
-	 * been signaled. The disable has to be last (after
-	 * drm_handle_vblank_events) so that the timestamp is always accurate.
-	 */
-	disable_irq = (dev->vblank_disable_immediate &&
-		       drm_vblank_offdelay > 0 &&
-		       !atomic_read(&vblank->refcount));
-
-	drm_handle_vblank_events(dev, pipe);
-
-	spin_unlock_irqrestore(&dev->event_lock, irqflags);
-
-	if (disable_irq)
-		vblank_disable_fn((unsigned long)vblank);
-
-	return true;
-}
-EXPORT_SYMBOL(drm_handle_vblank);
-
-/**
- * drm_crtc_handle_vblank - handle a vblank event
- * @crtc: where this event occurred
- *
- * Drivers should call this routine in their vblank interrupt handlers to
- * update the vblank counter and send any signals that may be pending.
- *
- * This is the native KMS version of drm_handle_vblank().
- *
- * Returns:
- * True if the event was successfully handled, false on failure.
- */
-bool drm_crtc_handle_vblank(struct drm_crtc *crtc)
-{
-	return drm_handle_vblank(crtc->dev, drm_crtc_index(crtc));
-}
-EXPORT_SYMBOL(drm_crtc_handle_vblank);
diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
new file mode 100644
index 000000000000..630dc26379b7
--- /dev/null
+++ b/drivers/gpu/drm/drm_vblank.c
@@ -0,0 +1,1645 @@
+/*
+ * drm_irq.c IRQ and vblank support
+ *
+ * \author Rickard E. (Rik) Faith <faith@valinux.com>
+ * \author Gareth Hughes <gareth@valinux.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <drm/drm_vblank.h>
+#include <drm/drmP.h>
+#include <linux/export.h>
+
+#include "drm_trace.h"
+#include "drm_internal.h"
+
+/* Retry timestamp calculation up to 3 times to satisfy
+ * drm_timestamp_precision before giving up.
+ */
+#define DRM_TIMESTAMP_MAXRETRIES 3
+
+/* Threshold in nanoseconds for detection of redundant
+ * vblank irq in drm_handle_vblank(). 1 msec should be ok.
+ */
+#define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000
+
+static bool
+drm_get_last_vbltimestamp(struct drm_device *dev, unsigned int pipe,
+			  struct timeval *tvblank, bool in_vblank_irq);
+
+static unsigned int drm_timestamp_precision = 20;  /* Default to 20 usecs. */
+
+/*
+ * Default to use monotonic timestamps for wait-for-vblank and page-flip
+ * complete events.
+ */
+unsigned int drm_timestamp_monotonic = 1;
+
+static int drm_vblank_offdelay = 5000;    /* Default to 5000 msecs. */
+
+module_param_named(vblankoffdelay, drm_vblank_offdelay, int, 0600);
+module_param_named(timestamp_precision_usec, drm_timestamp_precision, int, 0600);
+module_param_named(timestamp_monotonic, drm_timestamp_monotonic, int, 0600);
+MODULE_PARM_DESC(vblankoffdelay, "Delay until vblank irq auto-disable [msecs] (0: never disable, <0: disable immediately)");
+MODULE_PARM_DESC(timestamp_precision_usec, "Max. error on timestamps [usecs]");
+MODULE_PARM_DESC(timestamp_monotonic, "Use monotonic timestamps");
+
+static void store_vblank(struct drm_device *dev, unsigned int pipe,
+			 u32 vblank_count_inc,
+			 struct timeval *t_vblank, u32 last)
+{
+	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
+
+	assert_spin_locked(&dev->vblank_time_lock);
+
+	vblank->last = last;
+
+	write_seqlock(&vblank->seqlock);
+	vblank->time = *t_vblank;
+	vblank->count += vblank_count_inc;
+	write_sequnlock(&vblank->seqlock);
+}
+
+/*
+ * "No hw counter" fallback implementation of .get_vblank_counter() hook,
+ * if there is no useable hardware frame counter available.
+ */
+static u32 drm_vblank_no_hw_counter(struct drm_device *dev, unsigned int pipe)
+{
+	WARN_ON_ONCE(dev->max_vblank_count != 0);
+	return 0;
+}
+
+static u32 __get_vblank_counter(struct drm_device *dev, unsigned int pipe)
+{
+	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
+		struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
+
+		if (crtc->funcs->get_vblank_counter)
+			return crtc->funcs->get_vblank_counter(crtc);
+	}
+
+	if (dev->driver->get_vblank_counter)
+		return dev->driver->get_vblank_counter(dev, pipe);
+
+	return drm_vblank_no_hw_counter(dev, pipe);
+}
+
+/*
+ * Reset the stored timestamp for the current vblank count to correspond
+ * to the last vblank occurred.
+ *
+ * Only to be called from drm_crtc_vblank_on().
+ *
+ * Note: caller must hold &drm_device.vbl_lock since this reads & writes
+ * device vblank fields.
+ */
+static void drm_reset_vblank_timestamp(struct drm_device *dev, unsigned int pipe)
+{
+	u32 cur_vblank;
+	bool rc;
+	struct timeval t_vblank;
+	int count = DRM_TIMESTAMP_MAXRETRIES;
+
+	spin_lock(&dev->vblank_time_lock);
+
+	/*
+	 * sample the current counter to avoid random jumps
+	 * when drm_vblank_enable() applies the diff
+	 */
+	do {
+		cur_vblank = __get_vblank_counter(dev, pipe);
+		rc = drm_get_last_vbltimestamp(dev, pipe, &t_vblank, false);
+	} while (cur_vblank != __get_vblank_counter(dev, pipe) && --count > 0);
+
+	/*
+	 * Only reinitialize corresponding vblank timestamp if high-precision query
+	 * available and didn't fail. Otherwise reinitialize delayed at next vblank
+	 * interrupt and assign 0 for now, to mark the vblanktimestamp as invalid.
+	 */
+	if (!rc)
+		t_vblank = (struct timeval) {0, 0};
+
+	/*
+	 * +1 to make sure user will never see the same
+	 * vblank counter value before and after a modeset
+	 */
+	store_vblank(dev, pipe, 1, &t_vblank, cur_vblank);
+
+	spin_unlock(&dev->vblank_time_lock);
+}
+
+/*
+ * Call back into the driver to update the appropriate vblank counter
+ * (specified by @pipe).  Deal with wraparound, if it occurred, and
+ * update the last read value so we can deal with wraparound on the next
+ * call if necessary.
+ *
+ * Only necessary when going from off->on, to account for frames we
+ * didn't get an interrupt for.
+ *
+ * Note: caller must hold &drm_device.vbl_lock since this reads & writes
+ * device vblank fields.
+ */
+static void drm_update_vblank_count(struct drm_device *dev, unsigned int pipe,
+				    bool in_vblank_irq)
+{
+	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
+	u32 cur_vblank, diff;
+	bool rc;
+	struct timeval t_vblank;
+	int count = DRM_TIMESTAMP_MAXRETRIES;
+	int framedur_ns = vblank->framedur_ns;
+
+	/*
+	 * Interrupts were disabled prior to this call, so deal with counter
+	 * wrap if needed.
+	 * NOTE!  It's possible we lost a full dev->max_vblank_count + 1 events
+	 * here if the register is small or we had vblank interrupts off for
+	 * a long time.
+	 *
+	 * We repeat the hardware vblank counter & timestamp query until
+	 * we get consistent results. This to prevent races between gpu
+	 * updating its hardware counter while we are retrieving the
+	 * corresponding vblank timestamp.
+	 */
+	do {
+		cur_vblank = __get_vblank_counter(dev, pipe);
+		rc = drm_get_last_vbltimestamp(dev, pipe, &t_vblank, in_vblank_irq);
+	} while (cur_vblank != __get_vblank_counter(dev, pipe) && --count > 0);
+
+	if (dev->max_vblank_count != 0) {
+		/* trust the hw counter when it's around */
+		diff = (cur_vblank - vblank->last) & dev->max_vblank_count;
+	} else if (rc && framedur_ns) {
+		const struct timeval *t_old;
+		u64 diff_ns;
+
+		t_old = &vblank->time;
+		diff_ns = timeval_to_ns(&t_vblank) - timeval_to_ns(t_old);
+
+		/*
+		 * Figure out how many vblanks we've missed based
+		 * on the difference in the timestamps and the
+		 * frame/field duration.
+		 */
+		diff = DIV_ROUND_CLOSEST_ULL(diff_ns, framedur_ns);
+
+		if (diff == 0 && in_vblank_irq)
+			DRM_DEBUG_VBL("crtc %u: Redundant vblirq ignored."
+				      " diff_ns = %lld, framedur_ns = %d)\n",
+				      pipe, (long long) diff_ns, framedur_ns);
+	} else {
+		/* some kind of default for drivers w/o accurate vbl timestamping */
+		diff = in_vblank_irq ? 1 : 0;
+	}
+
+	/*
+	 * Within a drm_vblank_pre_modeset - drm_vblank_post_modeset
+	 * interval? If so then vblank irqs keep running and it will likely
+	 * happen that the hardware vblank counter is not trustworthy as it
+	 * might reset at some point in that interval and vblank timestamps
+	 * are not trustworthy either in that interval. Iow. this can result
+	 * in a bogus diff >> 1 which must be avoided as it would cause
+	 * random large forward jumps of the software vblank counter.
+	 */
+	if (diff > 1 && (vblank->inmodeset & 0x2)) {
+		DRM_DEBUG_VBL("clamping vblank bump to 1 on crtc %u: diffr=%u"
+			      " due to pre-modeset.\n", pipe, diff);
+		diff = 1;
+	}
+
+	DRM_DEBUG_VBL("updating vblank count on crtc %u:"
+		      " current=%u, diff=%u, hw=%u hw_last=%u\n",
+		      pipe, vblank->count, diff, cur_vblank, vblank->last);
+
+	if (diff == 0) {
+		WARN_ON_ONCE(cur_vblank != vblank->last);
+		return;
+	}
+
+	/*
+	 * Only reinitialize corresponding vblank timestamp if high-precision query
+	 * available and didn't fail, or we were called from the vblank interrupt.
+	 * Otherwise reinitialize delayed at next vblank interrupt and assign 0
+	 * for now, to mark the vblanktimestamp as invalid.
+	 */
+	if (!rc && in_vblank_irq)
+		t_vblank = (struct timeval) {0, 0};
+
+	store_vblank(dev, pipe, diff, &t_vblank, cur_vblank);
+}
+
+static u32 drm_vblank_count(struct drm_device *dev, unsigned int pipe)
+{
+	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
+
+	if (WARN_ON(pipe >= dev->num_crtcs))
+		return 0;
+
+	return vblank->count;
+}
+
+/**
+ * drm_accurate_vblank_count - retrieve the master vblank counter
+ * @crtc: which counter to retrieve
+ *
+ * This function is similar to @drm_crtc_vblank_count but this
+ * function interpolates to handle a race with vblank irq's.
+ *
+ * This is mostly useful for hardware that can obtain the scanout
+ * position, but doesn't have a frame counter.
+ */
+u32 drm_accurate_vblank_count(struct drm_crtc *crtc)
+{
+	struct drm_device *dev = crtc->dev;
+	unsigned int pipe = drm_crtc_index(crtc);
+	u32 vblank;
+	unsigned long flags;
+
+	WARN(!dev->driver->get_vblank_timestamp,
+	     "This function requires support for accurate vblank timestamps.");
+
+	spin_lock_irqsave(&dev->vblank_time_lock, flags);
+
+	drm_update_vblank_count(dev, pipe, false);
+	vblank = drm_vblank_count(dev, pipe);
+
+	spin_unlock_irqrestore(&dev->vblank_time_lock, flags);
+
+	return vblank;
+}
+EXPORT_SYMBOL(drm_accurate_vblank_count);
+
+static void __disable_vblank(struct drm_device *dev, unsigned int pipe)
+{
+	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
+		struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
+
+		if (crtc->funcs->disable_vblank) {
+			crtc->funcs->disable_vblank(crtc);
+			return;
+		}
+	}
+
+	dev->driver->disable_vblank(dev, pipe);
+}
+
+/*
+ * Disable vblank irq's on crtc, make sure that last vblank count
+ * of hardware and corresponding consistent software vblank counter
+ * are preserved, even if there are any spurious vblank irq's after
+ * disable.
+ */
+void drm_vblank_disable_and_save(struct drm_device *dev, unsigned int pipe)
+{
+	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
+	unsigned long irqflags;
+
+	assert_spin_locked(&dev->vbl_lock);
+
+	/* Prevent vblank irq processing while disabling vblank irqs,
+	 * so no updates of timestamps or count can happen after we've
+	 * disabled. Needed to prevent races in case of delayed irq's.
+	 */
+	spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
+
+	/*
+	 * Only disable vblank interrupts if they're enabled. This avoids
+	 * calling the ->disable_vblank() operation in atomic context with the
+	 * hardware potentially runtime suspended.
+	 */
+	if (vblank->enabled) {
+		__disable_vblank(dev, pipe);
+		vblank->enabled = false;
+	}
+
+	/*
+	 * Always update the count and timestamp to maintain the
+	 * appearance that the counter has been ticking all along until
+	 * this time. This makes the count account for the entire time
+	 * between drm_crtc_vblank_on() and drm_crtc_vblank_off().
+	 */
+	drm_update_vblank_count(dev, pipe, false);
+
+	spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
+}
+
+static void vblank_disable_fn(unsigned long arg)
+{
+	struct drm_vblank_crtc *vblank = (void *)arg;
+	struct drm_device *dev = vblank->dev;
+	unsigned int pipe = vblank->pipe;
+	unsigned long irqflags;
+
+	spin_lock_irqsave(&dev->vbl_lock, irqflags);
+	if (atomic_read(&vblank->refcount) == 0 && vblank->enabled) {
+		DRM_DEBUG("disabling vblank on crtc %u\n", pipe);
+		drm_vblank_disable_and_save(dev, pipe);
+	}
+	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
+}
+
+/**
+ * drm_vblank_cleanup - cleanup vblank support
+ * @dev: DRM device
+ *
+ * This function cleans up any resources allocated in drm_vblank_init.
+ */
+void drm_vblank_cleanup(struct drm_device *dev)
+{
+	unsigned int pipe;
+
+	/* Bail if the driver didn't call drm_vblank_init() */
+	if (dev->num_crtcs == 0)
+		return;
+
+	for (pipe = 0; pipe < dev->num_crtcs; pipe++) {
+		struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
+
+		WARN_ON(READ_ONCE(vblank->enabled) &&
+			drm_core_check_feature(dev, DRIVER_MODESET));
+
+		del_timer_sync(&vblank->disable_timer);
+	}
+
+	kfree(dev->vblank);
+
+	dev->num_crtcs = 0;
+}
+EXPORT_SYMBOL(drm_vblank_cleanup);
+
+/**
+ * drm_vblank_init - initialize vblank support
+ * @dev: DRM device
+ * @num_crtcs: number of CRTCs supported by @dev
+ *
+ * This function initializes vblank support for @num_crtcs display pipelines.
+ *
+ * Returns:
+ * Zero on success or a negative error code on failure.
+ */
+int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs)
+{
+	int ret = -ENOMEM;
+	unsigned int i;
+
+	spin_lock_init(&dev->vbl_lock);
+	spin_lock_init(&dev->vblank_time_lock);
+
+	dev->num_crtcs = num_crtcs;
+
+	dev->vblank = kcalloc(num_crtcs, sizeof(*dev->vblank), GFP_KERNEL);
+	if (!dev->vblank)
+		goto err;
+
+	for (i = 0; i < num_crtcs; i++) {
+		struct drm_vblank_crtc *vblank = &dev->vblank[i];
+
+		vblank->dev = dev;
+		vblank->pipe = i;
+		init_waitqueue_head(&vblank->queue);
+		setup_timer(&vblank->disable_timer, vblank_disable_fn,
+			    (unsigned long)vblank);
+		seqlock_init(&vblank->seqlock);
+	}
+
+	DRM_INFO("Supports vblank timestamp caching Rev 2 (21.10.2013).\n");
+
+	/* Driver specific high-precision vblank timestamping supported? */
+	if (dev->driver->get_vblank_timestamp)
+		DRM_INFO("Driver supports precise vblank timestamp query.\n");
+	else
+		DRM_INFO("No driver support for vblank timestamp query.\n");
+
+	/* Must have precise timestamping for reliable vblank instant disable */
+	if (dev->vblank_disable_immediate && !dev->driver->get_vblank_timestamp) {
+		dev->vblank_disable_immediate = false;
+		DRM_INFO("Setting vblank_disable_immediate to false because "
+			 "get_vblank_timestamp == NULL\n");
+	}
+
+	return 0;
+
+err:
+	dev->num_crtcs = 0;
+	return ret;
+}
+EXPORT_SYMBOL(drm_vblank_init);
+
+/**
+ * drm_crtc_vblank_waitqueue - get vblank waitqueue for the CRTC
+ * @crtc: which CRTC's vblank waitqueue to retrieve
+ *
+ * This function returns a pointer to the vblank waitqueue for the CRTC.
+ * Drivers can use this to implement vblank waits using wait_event() and related
+ * functions.
+ */
+wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc)
+{
+	return &crtc->dev->vblank[drm_crtc_index(crtc)].queue;
+}
+EXPORT_SYMBOL(drm_crtc_vblank_waitqueue);
+
+
+/**
+ * drm_calc_timestamping_constants - calculate vblank timestamp constants
+ * @crtc: drm_crtc whose timestamp constants should be updated.
+ * @mode: display mode containing the scanout timings
+ *
+ * Calculate and store various constants which are later
+ * needed by vblank and swap-completion timestamping, e.g,
+ * by drm_calc_vbltimestamp_from_scanoutpos(). They are
+ * derived from CRTC's true scanout timing, so they take
+ * things like panel scaling or other adjustments into account.
+ */
+void drm_calc_timestamping_constants(struct drm_crtc *crtc,
+				     const struct drm_display_mode *mode)
+{
+	struct drm_device *dev = crtc->dev;
+	unsigned int pipe = drm_crtc_index(crtc);
+	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
+	int linedur_ns = 0, framedur_ns = 0;
+	int dotclock = mode->crtc_clock;
+
+	if (!dev->num_crtcs)
+		return;
+
+	if (WARN_ON(pipe >= dev->num_crtcs))
+		return;
+
+	/* Valid dotclock? */
+	if (dotclock > 0) {
+		int frame_size = mode->crtc_htotal * mode->crtc_vtotal;
+
+		/*
+		 * Convert scanline length in pixels and video
+		 * dot clock to line duration and frame duration
+		 * in nanoseconds:
+		 */
+		linedur_ns  = div_u64((u64) mode->crtc_htotal * 1000000, dotclock);
+		framedur_ns = div_u64((u64) frame_size * 1000000, dotclock);
+
+		/*
+		 * Fields of interlaced scanout modes are only half a frame duration.
+		 */
+		if (mode->flags & DRM_MODE_FLAG_INTERLACE)
+			framedur_ns /= 2;
+	} else
+		DRM_ERROR("crtc %u: Can't calculate constants, dotclock = 0!\n",
+			  crtc->base.id);
+
+	vblank->linedur_ns  = linedur_ns;
+	vblank->framedur_ns = framedur_ns;
+	vblank->hwmode = *mode;
+
+	DRM_DEBUG("crtc %u: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
+		  crtc->base.id, mode->crtc_htotal,
+		  mode->crtc_vtotal, mode->crtc_vdisplay);
+	DRM_DEBUG("crtc %u: clock %d kHz framedur %d linedur %d\n",
+		  crtc->base.id, dotclock, framedur_ns, linedur_ns);
+}
+EXPORT_SYMBOL(drm_calc_timestamping_constants);
+
+/**
+ * drm_calc_vbltimestamp_from_scanoutpos - precise vblank timestamp helper
+ * @dev: DRM device
+ * @pipe: index of CRTC whose vblank timestamp to retrieve
+ * @max_error: Desired maximum allowable error in timestamps (nanosecs)
+ *             On return contains true maximum error of timestamp
+ * @vblank_time: Pointer to struct timeval which should receive the timestamp
+ * @in_vblank_irq:
+ *     True when called from drm_crtc_handle_vblank().  Some drivers
+ *     need to apply some workarounds for gpu-specific vblank irq quirks
+ *     if flag is set.
+ *
+ * Implements calculation of exact vblank timestamps from given drm_display_mode
+ * timings and current video scanout position of a CRTC. This can be called from
+ * within get_vblank_timestamp() implementation of a kms driver to implement the
+ * actual timestamping.
+ *
+ * Should return timestamps conforming to the OML_sync_control OpenML
+ * extension specification. The timestamp corresponds to the end of
+ * the vblank interval, aka start of scanout of topmost-leftmost display
+ * pixel in the following video frame.
+ *
+ * Requires support for optional dev->driver->get_scanout_position()
+ * in kms driver, plus a bit of setup code to provide a drm_display_mode
+ * that corresponds to the true scanout timing.
+ *
+ * The current implementation only handles standard video modes. It
+ * returns as no operation if a doublescan or interlaced video mode is
+ * active. Higher level code is expected to handle this.
+ *
+ * This function can be used to implement the &drm_driver.get_vblank_timestamp
+ * directly, if the driver implements the &drm_driver.get_scanout_position hook.
+ *
+ * Note that atomic drivers must call drm_calc_timestamping_constants() before
+ * enabling a CRTC. The atomic helpers already take care of that in
+ * drm_atomic_helper_update_legacy_modeset_state().
+ *
+ * Returns:
+ *
+ * Returns true on success, and false on failure, i.e. when no accurate
+ * timestamp could be acquired.
+ */
+bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
+					   unsigned int pipe,
+					   int *max_error,
+					   struct timeval *vblank_time,
+					   bool in_vblank_irq)
+{
+	struct timeval tv_etime;
+	ktime_t stime, etime;
+	bool vbl_status;
+	struct drm_crtc *crtc;
+	const struct drm_display_mode *mode;
+	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
+	int vpos, hpos, i;
+	int delta_ns, duration_ns;
+
+	if (!drm_core_check_feature(dev, DRIVER_MODESET))
+		return false;
+
+	crtc = drm_crtc_from_index(dev, pipe);
+
+	if (pipe >= dev->num_crtcs || !crtc) {
+		DRM_ERROR("Invalid crtc %u\n", pipe);
+		return false;
+	}
+
+	/* Scanout position query not supported? Should not happen. */
+	if (!dev->driver->get_scanout_position) {
+		DRM_ERROR("Called from driver w/o get_scanout_position()!?\n");
+		return false;
+	}
+
+	if (drm_drv_uses_atomic_modeset(dev))
+		mode = &vblank->hwmode;
+	else
+		mode = &crtc->hwmode;
+
+	/* If mode timing undefined, just return as no-op:
+	 * Happens during initial modesetting of a crtc.
+	 */
+	if (mode->crtc_clock == 0) {
+		DRM_DEBUG("crtc %u: Noop due to uninitialized mode.\n", pipe);
+		WARN_ON_ONCE(drm_drv_uses_atomic_modeset(dev));
+
+		return false;
+	}
+
+	/* Get current scanout position with system timestamp.
+	 * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times
+	 * if single query takes longer than max_error nanoseconds.
+	 *
+	 * This guarantees a tight bound on maximum error if
+	 * code gets preempted or delayed for some reason.
+	 */
+	for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) {
+		/*
+		 * Get vertical and horizontal scanout position vpos, hpos,
+		 * and bounding timestamps stime, etime, pre/post query.
+		 */
+		vbl_status = dev->driver->get_scanout_position(dev, pipe,
+							       in_vblank_irq,
+							       &vpos, &hpos,
+							       &stime, &etime,
+							       mode);
+
+		/* Return as no-op if scanout query unsupported or failed. */
+		if (!vbl_status) {
+			DRM_DEBUG("crtc %u : scanoutpos query failed.\n",
+				  pipe);
+			return false;
+		}
+
+		/* Compute uncertainty in timestamp of scanout position query. */
+		duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime);
+
+		/* Accept result with <  max_error nsecs timing uncertainty. */
+		if (duration_ns <= *max_error)
+			break;
+	}
+
+	/* Noisy system timing? */
+	if (i == DRM_TIMESTAMP_MAXRETRIES) {
+		DRM_DEBUG("crtc %u: Noisy timestamp %d us > %d us [%d reps].\n",
+			  pipe, duration_ns/1000, *max_error/1000, i);
+	}
+
+	/* Return upper bound of timestamp precision error. */
+	*max_error = duration_ns;
+
+	/* Convert scanout position into elapsed time at raw_time query
+	 * since start of scanout at first display scanline. delta_ns
+	 * can be negative if start of scanout hasn't happened yet.
+	 */
+	delta_ns = div_s64(1000000LL * (vpos * mode->crtc_htotal + hpos),
+			   mode->crtc_clock);
+
+	if (!drm_timestamp_monotonic)
+		etime = ktime_mono_to_real(etime);
+
+	/* save this only for debugging purposes */
+	tv_etime = ktime_to_timeval(etime);
+	/* Subtract time delta from raw timestamp to get final
+	 * vblank_time timestamp for end of vblank.
+	 */
+	etime = ktime_sub_ns(etime, delta_ns);
+	*vblank_time = ktime_to_timeval(etime);
+
+	DRM_DEBUG_VBL("crtc %u : v p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n",
+		      pipe, hpos, vpos,
+		      (long)tv_etime.tv_sec, (long)tv_etime.tv_usec,
+		      (long)vblank_time->tv_sec, (long)vblank_time->tv_usec,
+		      duration_ns/1000, i);
+
+	return true;
+}
+EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);
+
+static struct timeval get_drm_timestamp(void)
+{
+	ktime_t now;
+
+	now = drm_timestamp_monotonic ? ktime_get() : ktime_get_real();
+	return ktime_to_timeval(now);
+}
+
+/**
+ * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent
+ *                             vblank interval
+ * @dev: DRM device
+ * @pipe: index of CRTC whose vblank timestamp to retrieve
+ * @tvblank: Pointer to target struct timeval which should receive the timestamp
+ * @in_vblank_irq:
+ *     True when called from drm_crtc_handle_vblank().  Some drivers
+ *     need to apply some workarounds for gpu-specific vblank irq quirks
+ *     if flag is set.
+ *
+ * Fetches the system timestamp corresponding to the time of the most recent
+ * vblank interval on specified CRTC. May call into kms-driver to
+ * compute the timestamp with a high-precision GPU specific method.
+ *
+ * Returns zero if timestamp originates from uncorrected do_gettimeofday()
+ * call, i.e., it isn't very precisely locked to the true vblank.
+ *
+ * Returns:
+ * True if timestamp is considered to be very precise, false otherwise.
+ */
+static bool
+drm_get_last_vbltimestamp(struct drm_device *dev, unsigned int pipe,
+			  struct timeval *tvblank, bool in_vblank_irq)
+{
+	bool ret = false;
+
+	/* Define requested maximum error on timestamps (nanoseconds). */
+	int max_error = (int) drm_timestamp_precision * 1000;
+
+	/* Query driver if possible and precision timestamping enabled. */
+	if (dev->driver->get_vblank_timestamp && (max_error > 0))
+		ret = dev->driver->get_vblank_timestamp(dev, pipe, &max_error,
+							tvblank, in_vblank_irq);
+
+	/* GPU high precision timestamp query unsupported or failed.
+	 * Return current monotonic/gettimeofday timestamp as best estimate.
+	 */
+	if (!ret)
+		*tvblank = get_drm_timestamp();
+
+	return ret;
+}
+
+/**
+ * drm_crtc_vblank_count - retrieve "cooked" vblank counter value
+ * @crtc: which counter to retrieve
+ *
+ * Fetches the "cooked" vblank count value that represents the number of
+ * vblank events since the system was booted, including lost events due to
+ * modesetting activity.
+ *
+ * Returns:
+ * The software vblank counter.
+ */
+u32 drm_crtc_vblank_count(struct drm_crtc *crtc)
+{
+	return drm_vblank_count(crtc->dev, drm_crtc_index(crtc));
+}
+EXPORT_SYMBOL(drm_crtc_vblank_count);
+
+/**
+ * drm_vblank_count_and_time - retrieve "cooked" vblank counter value and the
+ *     system timestamp corresponding to that vblank counter value.
+ * @dev: DRM device
+ * @pipe: index of CRTC whose counter to retrieve
+ * @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
+ *
+ * Fetches the "cooked" vblank count value that represents the number of
+ * vblank events since the system was booted, including lost events due to
+ * modesetting activity. Returns corresponding system timestamp of the time
+ * of the vblank interval that corresponds to the current vblank counter value.
+ *
+ * This is the legacy version of drm_crtc_vblank_count_and_time().
+ */
+static u32 drm_vblank_count_and_time(struct drm_device *dev, unsigned int pipe,
+				     struct timeval *vblanktime)
+{
+	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
+	u32 vblank_count;
+	unsigned int seq;
+
+	if (WARN_ON(pipe >= dev->num_crtcs)) {
+		*vblanktime = (struct timeval) { 0 };
+		return 0;
+	}
+
+	do {
+		seq = read_seqbegin(&vblank->seqlock);
+		vblank_count = vblank->count;
+		*vblanktime = vblank->time;
+	} while (read_seqretry(&vblank->seqlock, seq));
+
+	return vblank_count;
+}
+
+/**
+ * drm_crtc_vblank_count_and_time - retrieve "cooked" vblank counter value
+ *     and the system timestamp corresponding to that vblank counter value
+ * @crtc: which counter to retrieve
+ * @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
+ *
+ * Fetches the "cooked" vblank count value that represents the number of
+ * vblank events since the system was booted, including lost events due to
+ * modesetting activity. Returns corresponding system timestamp of the time
+ * of the vblank interval that corresponds to the current vblank counter value.
+ */
+u32 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
+				   struct timeval *vblanktime)
+{
+	return drm_vblank_count_and_time(crtc->dev, drm_crtc_index(crtc),
+					 vblanktime);
+}
+EXPORT_SYMBOL(drm_crtc_vblank_count_and_time);
+
+static void send_vblank_event(struct drm_device *dev,
+		struct drm_pending_vblank_event *e,
+		unsigned long seq, struct timeval *now)
+{
+	e->event.sequence = seq;
+	e->event.tv_sec = now->tv_sec;
+	e->event.tv_usec = now->tv_usec;
+
+	trace_drm_vblank_event_delivered(e->base.file_priv, e->pipe,
+					 e->event.sequence);
+
+	drm_send_event_locked(dev, &e->base);
+}
+
+/**
+ * drm_crtc_arm_vblank_event - arm vblank event after pageflip
+ * @crtc: the source CRTC of the vblank event
+ * @e: the event to send
+ *
+ * A lot of drivers need to generate vblank events for the very next vblank
+ * interrupt. For example when the page flip interrupt happens when the page
+ * flip gets armed, but not when it actually executes within the next vblank
+ * period. This helper function implements exactly the required vblank arming
+ * behaviour.
+ *
+ * NOTE: Drivers using this to send out the &drm_crtc_state.event as part of an
+ * atomic commit must ensure that the next vblank happens at exactly the same
+ * time as the atomic commit is committed to the hardware. This function itself
+ * does **not** protect again the next vblank interrupt racing with either this
+ * function call or the atomic commit operation. A possible sequence could be:
+ *
+ * 1. Driver commits new hardware state into vblank-synchronized registers.
+ * 2. A vblank happens, committing the hardware state. Also the corresponding
+ *    vblank interrupt is fired off and fully processed by the interrupt
+ *    handler.
+ * 3. The atomic commit operation proceeds to call drm_crtc_arm_vblank_event().
+ * 4. The event is only send out for the next vblank, which is wrong.
+ *
+ * An equivalent race can happen when the driver calls
+ * drm_crtc_arm_vblank_event() before writing out the new hardware state.
+ *
+ * The only way to make this work safely is to prevent the vblank from firing
+ * (and the hardware from committing anything else) until the entire atomic
+ * commit sequence has run to completion. If the hardware does not have such a
+ * feature (e.g. using a "go" bit), then it is unsafe to use this functions.
+ * Instead drivers need to manually send out the event from their interrupt
+ * handler by calling drm_crtc_send_vblank_event() and make sure that there's no
+ * possible race with the hardware committing the atomic update.
+ *
+ * Caller must hold event lock. Caller must also hold a vblank reference for
+ * the event @e, which will be dropped when the next vblank arrives.
+ */
+void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
+			       struct drm_pending_vblank_event *e)
+{
+	struct drm_device *dev = crtc->dev;
+	unsigned int pipe = drm_crtc_index(crtc);
+
+	assert_spin_locked(&dev->event_lock);
+
+	e->pipe = pipe;
+	e->event.sequence = drm_vblank_count(dev, pipe);
+	e->event.crtc_id = crtc->base.id;
+	list_add_tail(&e->base.link, &dev->vblank_event_list);
+}
+EXPORT_SYMBOL(drm_crtc_arm_vblank_event);
+
+/**
+ * drm_crtc_send_vblank_event - helper to send vblank event after pageflip
+ * @crtc: the source CRTC of the vblank event
+ * @e: the event to send
+ *
+ * Updates sequence # and timestamp on event for the most recently processed
+ * vblank, and sends it to userspace.  Caller must hold event lock.
+ *
+ * See drm_crtc_arm_vblank_event() for a helper which can be used in certain
+ * situation, especially to send out events for atomic commit operations.
+ */
+void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
+				struct drm_pending_vblank_event *e)
+{
+	struct drm_device *dev = crtc->dev;
+	unsigned int seq, pipe = drm_crtc_index(crtc);
+	struct timeval now;
+
+	if (dev->num_crtcs > 0) {
+		seq = drm_vblank_count_and_time(dev, pipe, &now);
+	} else {
+		seq = 0;
+
+		now = get_drm_timestamp();
+	}
+	e->pipe = pipe;
+	e->event.crtc_id = crtc->base.id;
+	send_vblank_event(dev, e, seq, &now);
+}
+EXPORT_SYMBOL(drm_crtc_send_vblank_event);
+
+static int __enable_vblank(struct drm_device *dev, unsigned int pipe)
+{
+	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
+		struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
+
+		if (crtc->funcs->enable_vblank)
+			return crtc->funcs->enable_vblank(crtc);
+	}
+
+	return dev->driver->enable_vblank(dev, pipe);
+}
+
+/**
+ * drm_vblank_enable - enable the vblank interrupt on a CRTC
+ * @dev: DRM device
+ * @pipe: CRTC index
+ *
+ * Returns:
+ * Zero on success or a negative error code on failure.
+ */
+static int drm_vblank_enable(struct drm_device *dev, unsigned int pipe)
+{
+	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
+	int ret = 0;
+
+	assert_spin_locked(&dev->vbl_lock);
+
+	spin_lock(&dev->vblank_time_lock);
+
+	if (!vblank->enabled) {
+		/*
+		 * Enable vblank irqs under vblank_time_lock protection.
+		 * All vblank count & timestamp updates are held off
+		 * until we are done reinitializing master counter and
+		 * timestamps. Filtercode in drm_handle_vblank() will
+		 * prevent double-accounting of same vblank interval.
+		 */
+		ret = __enable_vblank(dev, pipe);
+		DRM_DEBUG("enabling vblank on crtc %u, ret: %d\n", pipe, ret);
+		if (ret) {
+			atomic_dec(&vblank->refcount);
+		} else {
+			drm_update_vblank_count(dev, pipe, 0);
+			/* drm_update_vblank_count() includes a wmb so we just
+			 * need to ensure that the compiler emits the write
+			 * to mark the vblank as enabled after the call
+			 * to drm_update_vblank_count().
+			 */
+			WRITE_ONCE(vblank->enabled, true);
+		}
+	}
+
+	spin_unlock(&dev->vblank_time_lock);
+
+	return ret;
+}
+
+/**
+ * drm_vblank_get - get a reference count on vblank events
+ * @dev: DRM device
+ * @pipe: index of CRTC to own
+ *
+ * Acquire a reference count on vblank events to avoid having them disabled
+ * while in use.
+ *
+ * This is the legacy version of drm_crtc_vblank_get().
+ *
+ * Returns:
+ * Zero on success or a negative error code on failure.
+ */
+static int drm_vblank_get(struct drm_device *dev, unsigned int pipe)
+{
+	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
+	unsigned long irqflags;
+	int ret = 0;
+
+	if (!dev->num_crtcs)
+		return -EINVAL;
+
+	if (WARN_ON(pipe >= dev->num_crtcs))
+		return -EINVAL;
+
+	spin_lock_irqsave(&dev->vbl_lock, irqflags);
+	/* Going from 0->1 means we have to enable interrupts again */
+	if (atomic_add_return(1, &vblank->refcount) == 1) {
+		ret = drm_vblank_enable(dev, pipe);
+	} else {
+		if (!vblank->enabled) {
+			atomic_dec(&vblank->refcount);
+			ret = -EINVAL;
+		}
+	}
+	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
+
+	return ret;
+}
+
+/**
+ * drm_crtc_vblank_get - get a reference count on vblank events
+ * @crtc: which CRTC to own
+ *
+ * Acquire a reference count on vblank events to avoid having them disabled
+ * while in use.
+ *
+ * Returns:
+ * Zero on success or a negative error code on failure.
+ */
+int drm_crtc_vblank_get(struct drm_crtc *crtc)
+{
+	return drm_vblank_get(crtc->dev, drm_crtc_index(crtc));
+}
+EXPORT_SYMBOL(drm_crtc_vblank_get);
+
+/**
+ * drm_vblank_put - release ownership of vblank events
+ * @dev: DRM device
+ * @pipe: index of CRTC to release
+ *
+ * Release ownership of a given vblank counter, turning off interrupts
+ * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
+ *
+ * This is the legacy version of drm_crtc_vblank_put().
+ */
+static void drm_vblank_put(struct drm_device *dev, unsigned int pipe)
+{
+	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
+
+	if (WARN_ON(pipe >= dev->num_crtcs))
+		return;
+
+	if (WARN_ON(atomic_read(&vblank->refcount) == 0))
+		return;
+
+	/* Last user schedules interrupt disable */
+	if (atomic_dec_and_test(&vblank->refcount)) {
+		if (drm_vblank_offdelay == 0)
+			return;
+		else if (drm_vblank_offdelay < 0)
+			vblank_disable_fn((unsigned long)vblank);
+		else if (!dev->vblank_disable_immediate)
+			mod_timer(&vblank->disable_timer,
+				  jiffies + ((drm_vblank_offdelay * HZ)/1000));
+	}
+}
+
+/**
+ * drm_crtc_vblank_put - give up ownership of vblank events
+ * @crtc: which counter to give up
+ *
+ * Release ownership of a given vblank counter, turning off interrupts
+ * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
+ */
+void drm_crtc_vblank_put(struct drm_crtc *crtc)
+{
+	drm_vblank_put(crtc->dev, drm_crtc_index(crtc));
+}
+EXPORT_SYMBOL(drm_crtc_vblank_put);
+
+/**
+ * drm_wait_one_vblank - wait for one vblank
+ * @dev: DRM device
+ * @pipe: CRTC index
+ *
+ * This waits for one vblank to pass on @pipe, using the irq driver interfaces.
+ * It is a failure to call this when the vblank irq for @pipe is disabled, e.g.
+ * due to lack of driver support or because the crtc is off.
+ */
+void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe)
+{
+	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
+	int ret;
+	u32 last;
+
+	if (WARN_ON(pipe >= dev->num_crtcs))
+		return;
+
+	ret = drm_vblank_get(dev, pipe);
+	if (WARN(ret, "vblank not available on crtc %i, ret=%i\n", pipe, ret))
+		return;
+
+	last = drm_vblank_count(dev, pipe);
+
+	ret = wait_event_timeout(vblank->queue,
+				 last != drm_vblank_count(dev, pipe),
+				 msecs_to_jiffies(100));
+
+	WARN(ret == 0, "vblank wait timed out on crtc %i\n", pipe);
+
+	drm_vblank_put(dev, pipe);
+}
+EXPORT_SYMBOL(drm_wait_one_vblank);
+
+/**
+ * drm_crtc_wait_one_vblank - wait for one vblank
+ * @crtc: DRM crtc
+ *
+ * This waits for one vblank to pass on @crtc, using the irq driver interfaces.
+ * It is a failure to call this when the vblank irq for @crtc is disabled, e.g.
+ * due to lack of driver support or because the crtc is off.
+ */
+void drm_crtc_wait_one_vblank(struct drm_crtc *crtc)
+{
+	drm_wait_one_vblank(crtc->dev, drm_crtc_index(crtc));
+}
+EXPORT_SYMBOL(drm_crtc_wait_one_vblank);
+
+/**
+ * drm_crtc_vblank_off - disable vblank events on a CRTC
+ * @crtc: CRTC in question
+ *
+ * Drivers can use this function to shut down the vblank interrupt handling when
+ * disabling a crtc. This function ensures that the latest vblank frame count is
+ * stored so that drm_vblank_on can restore it again.
+ *
+ * Drivers must use this function when the hardware vblank counter can get
+ * reset, e.g. when suspending.
+ */
+void drm_crtc_vblank_off(struct drm_crtc *crtc)
+{
+	struct drm_device *dev = crtc->dev;
+	unsigned int pipe = drm_crtc_index(crtc);
+	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
+	struct drm_pending_vblank_event *e, *t;
+	struct timeval now;
+	unsigned long irqflags;
+	unsigned int seq;
+
+	if (WARN_ON(pipe >= dev->num_crtcs))
+		return;
+
+	spin_lock_irqsave(&dev->event_lock, irqflags);
+
+	spin_lock(&dev->vbl_lock);
+	DRM_DEBUG_VBL("crtc %d, vblank enabled %d, inmodeset %d\n",
+		      pipe, vblank->enabled, vblank->inmodeset);
+
+	/* Avoid redundant vblank disables without previous
+	 * drm_crtc_vblank_on(). */
+	if (drm_core_check_feature(dev, DRIVER_ATOMIC) || !vblank->inmodeset)
+		drm_vblank_disable_and_save(dev, pipe);
+
+	wake_up(&vblank->queue);
+
+	/*
+	 * Prevent subsequent drm_vblank_get() from re-enabling
+	 * the vblank interrupt by bumping the refcount.
+	 */
+	if (!vblank->inmodeset) {
+		atomic_inc(&vblank->refcount);
+		vblank->inmodeset = 1;
+	}
+	spin_unlock(&dev->vbl_lock);
+
+	/* Send any queued vblank events, lest the natives grow disquiet */
+	seq = drm_vblank_count_and_time(dev, pipe, &now);
+
+	list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
+		if (e->pipe != pipe)
+			continue;
+		DRM_DEBUG("Sending premature vblank event on disable: "
+			  "wanted %u, current %u\n",
+			  e->event.sequence, seq);
+		list_del(&e->base.link);
+		drm_vblank_put(dev, pipe);
+		send_vblank_event(dev, e, seq, &now);
+	}
+	spin_unlock_irqrestore(&dev->event_lock, irqflags);
+
+	/* Will be reset by the modeset helpers when re-enabling the crtc by
+	 * calling drm_calc_timestamping_constants(). */
+	vblank->hwmode.crtc_clock = 0;
+}
+EXPORT_SYMBOL(drm_crtc_vblank_off);
+
+/**
+ * drm_crtc_vblank_reset - reset vblank state to off on a CRTC
+ * @crtc: CRTC in question
+ *
+ * Drivers can use this function to reset the vblank state to off at load time.
+ * Drivers should use this together with the drm_crtc_vblank_off() and
+ * drm_crtc_vblank_on() functions. The difference compared to
+ * drm_crtc_vblank_off() is that this function doesn't save the vblank counter
+ * and hence doesn't need to call any driver hooks.
+ */
+void drm_crtc_vblank_reset(struct drm_crtc *crtc)
+{
+	struct drm_device *dev = crtc->dev;
+	unsigned long irqflags;
+	unsigned int pipe = drm_crtc_index(crtc);
+	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
+
+	spin_lock_irqsave(&dev->vbl_lock, irqflags);
+	/*
+	 * Prevent subsequent drm_vblank_get() from enabling the vblank
+	 * interrupt by bumping the refcount.
+	 */
+	if (!vblank->inmodeset) {
+		atomic_inc(&vblank->refcount);
+		vblank->inmodeset = 1;
+	}
+	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
+
+	WARN_ON(!list_empty(&dev->vblank_event_list));
+}
+EXPORT_SYMBOL(drm_crtc_vblank_reset);
+
+/**
+ * drm_crtc_vblank_on - enable vblank events on a CRTC
+ * @crtc: CRTC in question
+ *
+ * This functions restores the vblank interrupt state captured with
+ * drm_crtc_vblank_off() again. Note that calls to drm_crtc_vblank_on() and
+ * drm_crtc_vblank_off() can be unbalanced and so can also be unconditionally called
+ * in driver load code to reflect the current hardware state of the crtc.
+ */
+void drm_crtc_vblank_on(struct drm_crtc *crtc)
+{
+	struct drm_device *dev = crtc->dev;
+	unsigned int pipe = drm_crtc_index(crtc);
+	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
+	unsigned long irqflags;
+
+	if (WARN_ON(pipe >= dev->num_crtcs))
+		return;
+
+	spin_lock_irqsave(&dev->vbl_lock, irqflags);
+	DRM_DEBUG_VBL("crtc %d, vblank enabled %d, inmodeset %d\n",
+		      pipe, vblank->enabled, vblank->inmodeset);
+
+	/* Drop our private "prevent drm_vblank_get" refcount */
+	if (vblank->inmodeset) {
+		atomic_dec(&vblank->refcount);
+		vblank->inmodeset = 0;
+	}
+
+	drm_reset_vblank_timestamp(dev, pipe);
+
+	/*
+	 * re-enable interrupts if there are users left, or the
+	 * user wishes vblank interrupts to be enabled all the time.
+	 */
+	if (atomic_read(&vblank->refcount) != 0 || drm_vblank_offdelay == 0)
+		WARN_ON(drm_vblank_enable(dev, pipe));
+	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
+}
+EXPORT_SYMBOL(drm_crtc_vblank_on);
+
+static void drm_legacy_vblank_pre_modeset(struct drm_device *dev,
+					  unsigned int pipe)
+{
+	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
+
+	/* vblank is not initialized (IRQ not installed ?), or has been freed */
+	if (!dev->num_crtcs)
+		return;
+
+	if (WARN_ON(pipe >= dev->num_crtcs))
+		return;
+
+	/*
+	 * To avoid all the problems that might happen if interrupts
+	 * were enabled/disabled around or between these calls, we just
+	 * have the kernel take a reference on the CRTC (just once though
+	 * to avoid corrupting the count if multiple, mismatch calls occur),
+	 * so that interrupts remain enabled in the interim.
+	 */
+	if (!vblank->inmodeset) {
+		vblank->inmodeset = 0x1;
+		if (drm_vblank_get(dev, pipe) == 0)
+			vblank->inmodeset |= 0x2;
+	}
+}
+
+static void drm_legacy_vblank_post_modeset(struct drm_device *dev,
+					   unsigned int pipe)
+{
+	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
+	unsigned long irqflags;
+
+	/* vblank is not initialized (IRQ not installed ?), or has been freed */
+	if (!dev->num_crtcs)
+		return;
+
+	if (WARN_ON(pipe >= dev->num_crtcs))
+		return;
+
+	if (vblank->inmodeset) {
+		spin_lock_irqsave(&dev->vbl_lock, irqflags);
+		drm_reset_vblank_timestamp(dev, pipe);
+		spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
+
+		if (vblank->inmodeset & 0x2)
+			drm_vblank_put(dev, pipe);
+
+		vblank->inmodeset = 0;
+	}
+}
+
+int drm_legacy_modeset_ctl(struct drm_device *dev, void *data,
+			   struct drm_file *file_priv)
+{
+	struct drm_modeset_ctl *modeset = data;
+	unsigned int pipe;
+
+	/* If drm_vblank_init() hasn't been called yet, just no-op */
+	if (!dev->num_crtcs)
+		return 0;
+
+	/* KMS drivers handle this internally */
+	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
+		return 0;
+
+	pipe = modeset->crtc;
+	if (pipe >= dev->num_crtcs)
+		return -EINVAL;
+
+	switch (modeset->cmd) {
+	case _DRM_PRE_MODESET:
+		drm_legacy_vblank_pre_modeset(dev, pipe);
+		break;
+	case _DRM_POST_MODESET:
+		drm_legacy_vblank_post_modeset(dev, pipe);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static inline bool vblank_passed(u32 seq, u32 ref)
+{
+	return (seq - ref) <= (1 << 23);
+}
+
+static int drm_queue_vblank_event(struct drm_device *dev, unsigned int pipe,
+				  union drm_wait_vblank *vblwait,
+				  struct drm_file *file_priv)
+{
+	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
+	struct drm_pending_vblank_event *e;
+	struct timeval now;
+	unsigned long flags;
+	unsigned int seq;
+	int ret;
+
+	e = kzalloc(sizeof(*e), GFP_KERNEL);
+	if (e == NULL) {
+		ret = -ENOMEM;
+		goto err_put;
+	}
+
+	e->pipe = pipe;
+	e->event.base.type = DRM_EVENT_VBLANK;
+	e->event.base.length = sizeof(e->event);
+	e->event.user_data = vblwait->request.signal;
+
+	spin_lock_irqsave(&dev->event_lock, flags);
+
+	/*
+	 * drm_crtc_vblank_off() might have been called after we called
+	 * drm_vblank_get(). drm_crtc_vblank_off() holds event_lock around the
+	 * vblank disable, so no need for further locking.  The reference from
+	 * drm_vblank_get() protects against vblank disable from another source.
+	 */
+	if (!READ_ONCE(vblank->enabled)) {
+		ret = -EINVAL;
+		goto err_unlock;
+	}
+
+	ret = drm_event_reserve_init_locked(dev, file_priv, &e->base,
+					    &e->event.base);
+
+	if (ret)
+		goto err_unlock;
+
+	seq = drm_vblank_count_and_time(dev, pipe, &now);
+
+	DRM_DEBUG("event on vblank count %u, current %u, crtc %u\n",
+		  vblwait->request.sequence, seq, pipe);
+
+	trace_drm_vblank_event_queued(file_priv, pipe,
+				      vblwait->request.sequence);
+
+	e->event.sequence = vblwait->request.sequence;
+	if (vblank_passed(seq, vblwait->request.sequence)) {
+		drm_vblank_put(dev, pipe);
+		send_vblank_event(dev, e, seq, &now);
+		vblwait->reply.sequence = seq;
+	} else {
+		/* drm_handle_vblank_events will call drm_vblank_put */
+		list_add_tail(&e->base.link, &dev->vblank_event_list);
+		vblwait->reply.sequence = vblwait->request.sequence;
+	}
+
+	spin_unlock_irqrestore(&dev->event_lock, flags);
+
+	return 0;
+
+err_unlock:
+	spin_unlock_irqrestore(&dev->event_lock, flags);
+	kfree(e);
+err_put:
+	drm_vblank_put(dev, pipe);
+	return ret;
+}
+
+static bool drm_wait_vblank_is_query(union drm_wait_vblank *vblwait)
+{
+	if (vblwait->request.sequence)
+		return false;
+
+	return _DRM_VBLANK_RELATIVE ==
+		(vblwait->request.type & (_DRM_VBLANK_TYPES_MASK |
+					  _DRM_VBLANK_EVENT |
+					  _DRM_VBLANK_NEXTONMISS));
+}
+
+/*
+ * Wait for VBLANK.
+ *
+ * \param inode device inode.
+ * \param file_priv DRM file private.
+ * \param cmd command.
+ * \param data user argument, pointing to a drm_wait_vblank structure.
+ * \return zero on success or a negative number on failure.
+ *
+ * This function enables the vblank interrupt on the pipe requested, then
+ * sleeps waiting for the requested sequence number to occur, and drops
+ * the vblank interrupt refcount afterwards. (vblank IRQ disable follows that
+ * after a timeout with no further vblank waits scheduled).
+ */
+int drm_wait_vblank(struct drm_device *dev, void *data,
+		    struct drm_file *file_priv)
+{
+	struct drm_vblank_crtc *vblank;
+	union drm_wait_vblank *vblwait = data;
+	int ret;
+	unsigned int flags, seq, pipe, high_pipe;
+
+	if (!dev->irq_enabled)
+		return -EINVAL;
+
+	if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
+		return -EINVAL;
+
+	if (vblwait->request.type &
+	    ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
+	      _DRM_VBLANK_HIGH_CRTC_MASK)) {
+		DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
+			  vblwait->request.type,
+			  (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
+			   _DRM_VBLANK_HIGH_CRTC_MASK));
+		return -EINVAL;
+	}
+
+	flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
+	high_pipe = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK);
+	if (high_pipe)
+		pipe = high_pipe >> _DRM_VBLANK_HIGH_CRTC_SHIFT;
+	else
+		pipe = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
+	if (pipe >= dev->num_crtcs)
+		return -EINVAL;
+
+	vblank = &dev->vblank[pipe];
+
+	/* If the counter is currently enabled and accurate, short-circuit
+	 * queries to return the cached timestamp of the last vblank.
+	 */
+	if (dev->vblank_disable_immediate &&
+	    drm_wait_vblank_is_query(vblwait) &&
+	    READ_ONCE(vblank->enabled)) {
+		struct timeval now;
+
+		vblwait->reply.sequence =
+			drm_vblank_count_and_time(dev, pipe, &now);
+		vblwait->reply.tval_sec = now.tv_sec;
+		vblwait->reply.tval_usec = now.tv_usec;
+		return 0;
+	}
+
+	ret = drm_vblank_get(dev, pipe);
+	if (ret) {
+		DRM_DEBUG("crtc %d failed to acquire vblank counter, %d\n", pipe, ret);
+		return ret;
+	}
+	seq = drm_vblank_count(dev, pipe);
+
+	switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
+	case _DRM_VBLANK_RELATIVE:
+		vblwait->request.sequence += seq;
+		vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
+	case _DRM_VBLANK_ABSOLUTE:
+		break;
+	default:
+		ret = -EINVAL;
+		goto done;
+	}
+
+	if ((flags & _DRM_VBLANK_NEXTONMISS) &&
+	    vblank_passed(seq, vblwait->request.sequence))
+		vblwait->request.sequence = seq + 1;
+
+	if (flags & _DRM_VBLANK_EVENT) {
+		/* must hold on to the vblank ref until the event fires
+		 * drm_vblank_put will be called asynchronously
+		 */
+		return drm_queue_vblank_event(dev, pipe, vblwait, file_priv);
+	}
+
+	if (vblwait->request.sequence != seq) {
+		DRM_DEBUG("waiting on vblank count %u, crtc %u\n",
+			  vblwait->request.sequence, pipe);
+		DRM_WAIT_ON(ret, vblank->queue, 3 * HZ,
+			    vblank_passed(drm_vblank_count(dev, pipe),
+					  vblwait->request.sequence) ||
+			    !READ_ONCE(vblank->enabled));
+	}
+
+	if (ret != -EINTR) {
+		struct timeval now;
+
+		vblwait->reply.sequence = drm_vblank_count_and_time(dev, pipe, &now);
+		vblwait->reply.tval_sec = now.tv_sec;
+		vblwait->reply.tval_usec = now.tv_usec;
+
+		DRM_DEBUG("crtc %d returning %u to client\n",
+			  pipe, vblwait->reply.sequence);
+	} else {
+		DRM_DEBUG("crtc %d vblank wait interrupted by signal\n", pipe);
+	}
+
+done:
+	drm_vblank_put(dev, pipe);
+	return ret;
+}
+
+static void drm_handle_vblank_events(struct drm_device *dev, unsigned int pipe)
+{
+	struct drm_pending_vblank_event *e, *t;
+	struct timeval now;
+	unsigned int seq;
+
+	assert_spin_locked(&dev->event_lock);
+
+	seq = drm_vblank_count_and_time(dev, pipe, &now);
+
+	list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
+		if (e->pipe != pipe)
+			continue;
+		if (!vblank_passed(seq, e->event.sequence))
+			continue;
+
+		DRM_DEBUG("vblank event on %u, current %u\n",
+			  e->event.sequence, seq);
+
+		list_del(&e->base.link);
+		drm_vblank_put(dev, pipe);
+		send_vblank_event(dev, e, seq, &now);
+	}
+
+	trace_drm_vblank_event(pipe, seq);
+}
+
+/**
+ * drm_handle_vblank - handle a vblank event
+ * @dev: DRM device
+ * @pipe: index of CRTC where this event occurred
+ *
+ * Drivers should call this routine in their vblank interrupt handlers to
+ * update the vblank counter and send any signals that may be pending.
+ *
+ * This is the legacy version of drm_crtc_handle_vblank().
+ */
+bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe)
+{
+	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
+	unsigned long irqflags;
+	bool disable_irq;
+
+	if (WARN_ON_ONCE(!dev->num_crtcs))
+		return false;
+
+	if (WARN_ON(pipe >= dev->num_crtcs))
+		return false;
+
+	spin_lock_irqsave(&dev->event_lock, irqflags);
+
+	/* Need timestamp lock to prevent concurrent execution with
+	 * vblank enable/disable, as this would cause inconsistent
+	 * or corrupted timestamps and vblank counts.
+	 */
+	spin_lock(&dev->vblank_time_lock);
+
+	/* Vblank irq handling disabled. Nothing to do. */
+	if (!vblank->enabled) {
+		spin_unlock(&dev->vblank_time_lock);
+		spin_unlock_irqrestore(&dev->event_lock, irqflags);
+		return false;
+	}
+
+	drm_update_vblank_count(dev, pipe, true);
+
+	spin_unlock(&dev->vblank_time_lock);
+
+	wake_up(&vblank->queue);
+
+	/* With instant-off, we defer disabling the interrupt until after
+	 * we finish processing the following vblank after all events have
+	 * been signaled. The disable has to be last (after
+	 * drm_handle_vblank_events) so that the timestamp is always accurate.
+	 */
+	disable_irq = (dev->vblank_disable_immediate &&
+		       drm_vblank_offdelay > 0 &&
+		       !atomic_read(&vblank->refcount));
+
+	drm_handle_vblank_events(dev, pipe);
+
+	spin_unlock_irqrestore(&dev->event_lock, irqflags);
+
+	if (disable_irq)
+		vblank_disable_fn((unsigned long)vblank);
+
+	return true;
+}
+EXPORT_SYMBOL(drm_handle_vblank);
+
+/**
+ * drm_crtc_handle_vblank - handle a vblank event
+ * @crtc: where this event occurred
+ *
+ * Drivers should call this routine in their vblank interrupt handlers to
+ * update the vblank counter and send any signals that may be pending.
+ *
+ * This is the native KMS version of drm_handle_vblank().
+ *
+ * Returns:
+ * True if the event was successfully handled, false on failure.
+ */
+bool drm_crtc_handle_vblank(struct drm_crtc *crtc)
+{
+	return drm_handle_vblank(crtc->dev, drm_crtc_index(crtc));
+}
+EXPORT_SYMBOL(drm_crtc_handle_vblank);
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index c363f2fdff31..2e0b76cceb97 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -80,6 +80,9 @@
 #include <drm/drm_debugfs.h>
 #include <drm/drm_ioctl.h>
 #include <drm/drm_sysfs.h>
+#include <drm/drm_vblank.h>
+#include <drm/drm_irq.h>
+
 
 struct module;
 
@@ -447,8 +450,6 @@ static inline bool drm_drv_uses_atomic_modeset(struct drm_device *dev)
 	return dev->mode_config.funcs->atomic_commit != NULL;
 }
 
-#include <drm/drm_irq.h>
-
 #define DRM_SWITCH_POWER_ON 0
 #define DRM_SWITCH_POWER_OFF 1
 #define DRM_SWITCH_POWER_CHANGING 2
diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
index 5dd27ae5c47c..d66f7ee07fb5 100644
--- a/include/drm/drm_file.h
+++ b/include/drm/drm_file.h
@@ -40,6 +40,7 @@
 struct dma_fence;
 struct drm_file;
 struct drm_device;
+struct device;
 
 /*
  * FIXME: Not sure we want to have drm_minor here in the end, but to avoid
diff --git a/include/drm/drm_irq.h b/include/drm/drm_irq.h
index 569ca86d4e1f..d77f6e65b1c6 100644
--- a/include/drm/drm_irq.h
+++ b/include/drm/drm_irq.h
@@ -24,165 +24,9 @@
 #ifndef _DRM_IRQ_H_
 #define _DRM_IRQ_H_
 
-#include <linux/seqlock.h>
-
-/**
- * struct drm_pending_vblank_event - pending vblank event tracking
- */
-struct drm_pending_vblank_event {
-	/**
-	 * @base: Base structure for tracking pending DRM events.
-	 */
-	struct drm_pending_event base;
-	/**
-	 * @pipe: drm_crtc_index() of the &drm_crtc this event is for.
-	 */
-	unsigned int pipe;
-	/**
-	 * @event: Actual event which will be sent to userspace.
-	 */
-	struct drm_event_vblank event;
-};
-
-/**
- * struct drm_vblank_crtc - vblank tracking for a CRTC
- *
- * This structure tracks the vblank state for one CRTC.
- *
- * Note that for historical reasons - the vblank handling code is still shared
- * with legacy/non-kms drivers - this is a free-standing structure not directly
- * connected to &struct drm_crtc. But all public interface functions are taking
- * a &struct drm_crtc to hide this implementation detail.
- */
-struct drm_vblank_crtc {
-	/**
-	 * @dev: Pointer to the &drm_device.
-	 */
-	struct drm_device *dev;
-	/**
-	 * @queue: Wait queue for vblank waiters.
-	 */
-	wait_queue_head_t queue;	/**< VBLANK wait queue */
-	/**
-	 * @disable_timer: Disable timer for the delayed vblank disabling
-	 * hysteresis logic. Vblank disabling is controlled through the
-	 * drm_vblank_offdelay module option and the setting of the
-	 * &drm_device.max_vblank_count value.
-	 */
-	struct timer_list disable_timer;
-
-	/**
-	 * @seqlock: Protect vblank count and time.
-	 */
-	seqlock_t seqlock;		/* protects vblank count and time */
-
-	/**
-	 * @count: Current software vblank counter.
-	 */
-	u32 count;
-	/**
-	 * @time: Vblank timestamp corresponding to @count.
-	 */
-	struct timeval time;
-
-	/**
-	 * @refcount: Number of users/waiters of the vblank interrupt. Only when
-	 * this refcount reaches 0 can the hardware interrupt be disabled using
-	 * @disable_timer.
-	 */
-	atomic_t refcount;		/* number of users of vblank interruptsper crtc */
-	/**
-	 * @last: Protected by &drm_device.vbl_lock, used for wraparound handling.
-	 */
-	u32 last;
-	/**
-	 * @inmodeset: Tracks whether the vblank is disabled due to a modeset.
-	 * For legacy driver bit 2 additionally tracks whether an additional
-	 * temporary vblank reference has been acquired to paper over the
-	 * hardware counter resetting/jumping. KMS drivers should instead just
-	 * call drm_crtc_vblank_off() and drm_crtc_vblank_on(), which explicitly
-	 * save and restore the vblank count.
-	 */
-	unsigned int inmodeset;		/* Display driver is setting mode */
-	/**
-	 * @pipe: drm_crtc_index() of the &drm_crtc corresponding to this
-	 * structure.
-	 */
-	unsigned int pipe;
-	/**
-	 * @framedur_ns: Frame/Field duration in ns, used by
-	 * drm_calc_vbltimestamp_from_scanoutpos() and computed by
-	 * drm_calc_timestamping_constants().
-	 */
-	int framedur_ns;
-	/**
-	 * @linedur_ns: Line duration in ns, used by
-	 * drm_calc_vbltimestamp_from_scanoutpos() and computed by
-	 * drm_calc_timestamping_constants().
-	 */
-	int linedur_ns;
-
-	/**
-	 * @hwmode:
-	 *
-	 * Cache of the current hardware display mode. Only valid when @enabled
-	 * is set. This is used by helpers like
-	 * drm_calc_vbltimestamp_from_scanoutpos(). We can't just access the
-	 * hardware mode by e.g. looking at &drm_crtc_state.adjusted_mode,
-	 * because that one is really hard to get from interrupt context.
-	 */
-	struct drm_display_mode hwmode;
-
-	/**
-	 * @enabled: Tracks the enabling state of the corresponding &drm_crtc to
-	 * avoid double-disabling and hence corrupting saved state. Needed by
-	 * drivers not using atomic KMS, since those might go through their CRTC
-	 * disabling functions multiple times.
-	 */
-	bool enabled;
-};
+struct drm_device;
 
 int drm_irq_install(struct drm_device *dev, int irq);
 int drm_irq_uninstall(struct drm_device *dev);
 
-int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs);
-u32 drm_crtc_vblank_count(struct drm_crtc *crtc);
-u32 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
-				   struct timeval *vblanktime);
-void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
-			       struct drm_pending_vblank_event *e);
-void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
-			      struct drm_pending_vblank_event *e);
-bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe);
-bool drm_crtc_handle_vblank(struct drm_crtc *crtc);
-int drm_crtc_vblank_get(struct drm_crtc *crtc);
-void drm_crtc_vblank_put(struct drm_crtc *crtc);
-void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe);
-void drm_crtc_wait_one_vblank(struct drm_crtc *crtc);
-void drm_crtc_vblank_off(struct drm_crtc *crtc);
-void drm_crtc_vblank_reset(struct drm_crtc *crtc);
-void drm_crtc_vblank_on(struct drm_crtc *crtc);
-void drm_vblank_cleanup(struct drm_device *dev);
-u32 drm_accurate_vblank_count(struct drm_crtc *crtc);
-
-bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
-					   unsigned int pipe, int *max_error,
-					   struct timeval *vblank_time,
-					   bool in_vblank_irq);
-void drm_calc_timestamping_constants(struct drm_crtc *crtc,
-				     const struct drm_display_mode *mode);
-
-/**
- * drm_crtc_vblank_waitqueue - get vblank waitqueue for the CRTC
- * @crtc: which CRTC's vblank waitqueue to retrieve
- *
- * This function returns a pointer to the vblank waitqueue for the CRTC.
- * Drivers can use this to implement vblank waits using wait_event() and related
- * functions.
- */
-static inline wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc)
-{
-	return &crtc->dev->vblank[drm_crtc_index(crtc)].queue;
-}
-
 #endif
diff --git a/include/drm/drm_prime.h b/include/drm/drm_prime.h
index 59ccab402e85..9cd9e36f77b5 100644
--- a/include/drm/drm_prime.h
+++ b/include/drm/drm_prime.h
@@ -59,6 +59,8 @@ struct drm_device;
 struct drm_gem_object;
 struct drm_file;
 
+struct device;
+
 struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
 				     struct drm_gem_object *obj,
 				     int flags);
diff --git a/include/drm/drm_vblank.h b/include/drm/drm_vblank.h
new file mode 100644
index 000000000000..4cde47332dfa
--- /dev/null
+++ b/include/drm/drm_vblank.h
@@ -0,0 +1,181 @@
+/*
+ * Copyright 2016 Intel Corp.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef _DRM_VBLANK_H_
+#define _DRM_VBLANK_H_
+
+#include <linux/seqlock.h>
+#include <linux/idr.h>
+#include <linux/poll.h>
+
+#include <drm/drm_file.h>
+#include <drm/drm_modes.h>
+#include <uapi/drm/drm.h>
+
+struct drm_device;
+struct drm_crtc;
+
+/**
+ * struct drm_pending_vblank_event - pending vblank event tracking
+ */
+struct drm_pending_vblank_event {
+	/**
+	 * @base: Base structure for tracking pending DRM events.
+	 */
+	struct drm_pending_event base;
+	/**
+	 * @pipe: drm_crtc_index() of the &drm_crtc this event is for.
+	 */
+	unsigned int pipe;
+	/**
+	 * @event: Actual event which will be sent to userspace.
+	 */
+	struct drm_event_vblank event;
+};
+
+/**
+ * struct drm_vblank_crtc - vblank tracking for a CRTC
+ *
+ * This structure tracks the vblank state for one CRTC.
+ *
+ * Note that for historical reasons - the vblank handling code is still shared
+ * with legacy/non-kms drivers - this is a free-standing structure not directly
+ * connected to &struct drm_crtc. But all public interface functions are taking
+ * a &struct drm_crtc to hide this implementation detail.
+ */
+struct drm_vblank_crtc {
+	/**
+	 * @dev: Pointer to the &drm_device.
+	 */
+	struct drm_device *dev;
+	/**
+	 * @queue: Wait queue for vblank waiters.
+	 */
+	wait_queue_head_t queue;	/**< VBLANK wait queue */
+	/**
+	 * @disable_timer: Disable timer for the delayed vblank disabling
+	 * hysteresis logic. Vblank disabling is controlled through the
+	 * drm_vblank_offdelay module option and the setting of the
+	 * &drm_device.max_vblank_count value.
+	 */
+	struct timer_list disable_timer;
+
+	/**
+	 * @seqlock: Protect vblank count and time.
+	 */
+	seqlock_t seqlock;		/* protects vblank count and time */
+
+	/**
+	 * @count: Current software vblank counter.
+	 */
+	u32 count;
+	/**
+	 * @time: Vblank timestamp corresponding to @count.
+	 */
+	struct timeval time;
+
+	/**
+	 * @refcount: Number of users/waiters of the vblank interrupt. Only when
+	 * this refcount reaches 0 can the hardware interrupt be disabled using
+	 * @disable_timer.
+	 */
+	atomic_t refcount;		/* number of users of vblank interruptsper crtc */
+	/**
+	 * @last: Protected by &drm_device.vbl_lock, used for wraparound handling.
+	 */
+	u32 last;
+	/**
+	 * @inmodeset: Tracks whether the vblank is disabled due to a modeset.
+	 * For legacy driver bit 2 additionally tracks whether an additional
+	 * temporary vblank reference has been acquired to paper over the
+	 * hardware counter resetting/jumping. KMS drivers should instead just
+	 * call drm_crtc_vblank_off() and drm_crtc_vblank_on(), which explicitly
+	 * save and restore the vblank count.
+	 */
+	unsigned int inmodeset;		/* Display driver is setting mode */
+	/**
+	 * @pipe: drm_crtc_index() of the &drm_crtc corresponding to this
+	 * structure.
+	 */
+	unsigned int pipe;
+	/**
+	 * @framedur_ns: Frame/Field duration in ns, used by
+	 * drm_calc_vbltimestamp_from_scanoutpos() and computed by
+	 * drm_calc_timestamping_constants().
+	 */
+	int framedur_ns;
+	/**
+	 * @linedur_ns: Line duration in ns, used by
+	 * drm_calc_vbltimestamp_from_scanoutpos() and computed by
+	 * drm_calc_timestamping_constants().
+	 */
+	int linedur_ns;
+
+	/**
+	 * @hwmode:
+	 *
+	 * Cache of the current hardware display mode. Only valid when @enabled
+	 * is set. This is used by helpers like
+	 * drm_calc_vbltimestamp_from_scanoutpos(). We can't just access the
+	 * hardware mode by e.g. looking at &drm_crtc_state.adjusted_mode,
+	 * because that one is really hard to get from interrupt context.
+	 */
+	struct drm_display_mode hwmode;
+
+	/**
+	 * @enabled: Tracks the enabling state of the corresponding &drm_crtc to
+	 * avoid double-disabling and hence corrupting saved state. Needed by
+	 * drivers not using atomic KMS, since those might go through their CRTC
+	 * disabling functions multiple times.
+	 */
+	bool enabled;
+};
+
+int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs);
+u32 drm_crtc_vblank_count(struct drm_crtc *crtc);
+u32 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
+				   struct timeval *vblanktime);
+void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
+			       struct drm_pending_vblank_event *e);
+void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
+			      struct drm_pending_vblank_event *e);
+bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe);
+bool drm_crtc_handle_vblank(struct drm_crtc *crtc);
+int drm_crtc_vblank_get(struct drm_crtc *crtc);
+void drm_crtc_vblank_put(struct drm_crtc *crtc);
+void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe);
+void drm_crtc_wait_one_vblank(struct drm_crtc *crtc);
+void drm_crtc_vblank_off(struct drm_crtc *crtc);
+void drm_crtc_vblank_reset(struct drm_crtc *crtc);
+void drm_crtc_vblank_on(struct drm_crtc *crtc);
+void drm_vblank_cleanup(struct drm_device *dev);
+u32 drm_accurate_vblank_count(struct drm_crtc *crtc);
+
+bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
+					   unsigned int pipe, int *max_error,
+					   struct timeval *vblank_time,
+					   bool in_vblank_irq);
+void drm_calc_timestamping_constants(struct drm_crtc *crtc,
+				     const struct drm_display_mode *mode);
+wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc);
+#endif
