[1/2] drm/i915: add fbc enable flag, but disable by default

Commit Message

Jesse Barnes May 5, 2011, 10:24 p.m. UTC

On Thu, 05 May 2011 18:07:43 -0400
Adam Jackson <[e-mail]> wrote:

> On 5/5/11 5:42 PM, Jesse Barnes wrote:
> > FBC has too many corner cases that we don't currently deal with, so
> > disable it by default so we can enable more important features like RC6,
> > which conflicts in some configurations.
> >
> > Signed-off-by: Jesse Barnes<[e-mail]>
> 
> It's a bit weird to ...
> 
> > +unsigned int i915_enable_fbc = 0;
> > +module_param_named(i915_enable_fbc, i915_enable_fbc, int, 0600);
> > +
> 
> ... disable fbc by default ...
> 
> > +	if (!i915_enable_fbc) {
> > +		DRM_DEBUG_KMS("fbc disabled manually\n");
> > +		dev_priv->no_fbc_reason = FBC_MANUAL_DISABLE;
> > +		goto out_disable;
> > +	}
> 
> ... and then claim the user is to blame.

Updated patch below.

Patch

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 52d2306..1e2e87f 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -1059,6 +1059,9 @@  static int i915_fbc_status(struct seq_file *m, void *unused)
 		case FBC_MULTIPLE_PIPES:
 			seq_printf(m, "multiple pipes are enabled");
 			break;
+		case FBC_MODULE_PARAM:
+			seq_printf(m, "disabled per module param (default off)");
+			break;
 		default:
 			seq_printf(m, "unknown reason");
 		}
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index b2a55d6..26bbb2f 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -55,6 +55,9 @@  module_param_named(semaphores, i915_semaphores, int, 0600);
 unsigned int i915_enable_rc6 = 0;
 module_param_named(i915_enable_rc6, i915_enable_rc6, int, 0600);
 
+unsigned int i915_enable_fbc = 0;
+module_param_named(i915_enable_fbc, i915_enable_fbc, int, 0600);
+
 unsigned int i915_lvds_downclock = 0;
 module_param_named(lvds_downclock, i915_lvds_downclock, int, 0400);
 
@@ -173,7 +176,7 @@  static const struct intel_device_info intel_ironlake_d_info = {
 static const struct intel_device_info intel_ironlake_m_info = {
 	.gen = 5, .is_mobile = 1,
 	.need_gfx_hws = 1, .has_hotplug = 1,
-	.has_fbc = 0, /* disabled due to buggy hardware */
+	.has_fbc = 1,
 	.has_bsd_ring = 1,
 };
 
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 02dea46..87e0622 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -251,6 +251,7 @@  enum no_fbc_reason {
 	FBC_BAD_PLANE, /* fbc not supported on plane */
 	FBC_NOT_TILED, /* buffer not tiled */
 	FBC_MULTIPLE_PIPES, /* more than one pipe active */
+	FBC_MODULE_PARAM,
 };
 
 enum intel_pch {
@@ -995,6 +996,7 @@  extern unsigned int i915_lvds_downclock;
 extern unsigned int i915_panel_use_ssc;
 extern int i915_vbt_sdvo_panel_type;
 extern unsigned int i915_enable_rc6;
+extern unsigned int i915_enable_fbc;
 
 extern int i915_suspend(struct drm_device *dev, pm_message_t state);
 extern int i915_resume(struct drm_device *dev);
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 6608f4c..3ef0c02 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1731,6 +1731,11 @@  static void intel_update_fbc(struct drm_device *dev)
 	intel_fb = to_intel_framebuffer(fb);
 	obj = intel_fb->obj;
 
+	if (!i915_enable_fbc) {
+		DRM_DEBUG_KMS("fbc disabled per module param (default off)\n");
+		dev_priv->no_fbc_reason = FBC_MODULE_PARAM;
+		goto out_disable;
+	}
 	if (intel_fb->obj->base.size > dev_priv->cfb_size) {
 		DRM_DEBUG_KMS("framebuffer too large, disabling "
 			      "compression\n");