@@ -550,6 +550,10 @@ struct intel_connector {
struct intel_dp *dp;
} mst;
+ struct {
+ int force_bpp_x16;
+ } link;
+
/* Work struct to schedule a uevent on link train failure */
struct work_struct modeset_retry_work;
@@ -3,6 +3,9 @@
* Copyright © 2023 Intel Corporation
*/
+#include <linux/debugfs.h>
+#include <linux/math.h>
+
#include <drm/drm_fixed.h>
#include <drm/drm_print.h>
@@ -10,11 +13,35 @@
#include "intel_crtc.h"
#include "intel_display_core.h"
#include "intel_display_types.h"
+#include "intel_dp.h"
#include "intel_dp_mst.h"
#include "intel_dp_tunnel.h"
#include "intel_fdi.h"
#include "intel_link_bw.h"
+static int get_forced_link_bpp_x16(struct intel_atomic_state *state,
+ const struct intel_crtc *crtc)
+{
+ struct drm_connector_state *conn_state;
+ struct drm_connector *_connector;
+ int force_bpp_x16 = INT_MAX;
+ int i;
+
+ for_each_new_connector_in_state(&state->base, _connector, conn_state, i) {
+ struct intel_connector *connector = to_intel_connector(_connector);
+
+ if (conn_state->crtc != &crtc->base)
+ continue;
+
+ if (!connector->link.force_bpp_x16)
+ continue;
+
+ force_bpp_x16 = min(force_bpp_x16, connector->link.force_bpp_x16);
+ }
+
+ return force_bpp_x16 < INT_MAX ? force_bpp_x16 : 0;
+}
+
/**
* intel_link_bw_init_limits - initialize BW limits
* @state: Atomic state
@@ -31,9 +58,10 @@ void intel_link_bw_init_limits(struct intel_atomic_state *state,
limits->force_fec_pipes = 0;
limits->bpp_limit_reached_pipes = 0;
for_each_pipe(display, pipe) {
+ struct intel_crtc *crtc = intel_crtc_for_pipe(display, pipe);
const struct intel_crtc_state *crtc_state =
- intel_atomic_get_new_crtc_state(state,
- intel_crtc_for_pipe(display, pipe));
+ intel_atomic_get_new_crtc_state(state, crtc);
+ int forced_bpp_x16 = get_forced_link_bpp_x16(state, crtc);
if (state->base.duplicated && crtc_state) {
limits->max_bpp_x16[pipe] = crtc_state->max_link_bpp_x16;
@@ -42,15 +70,19 @@ void intel_link_bw_init_limits(struct intel_atomic_state *state,
} else {
limits->max_bpp_x16[pipe] = INT_MAX;
}
+
+ if (forced_bpp_x16)
+ limits->max_bpp_x16[pipe] = min(limits->max_bpp_x16[pipe], forced_bpp_x16);
}
}
/**
- * intel_link_bw_reduce_bpp - reduce maximum link bpp for a selected pipe
+ * __intel_link_bw_reduce_bpp - reduce maximum link bpp for a selected pipe
* @state: atomic state
* @limits: link BW limits
* @pipe_mask: mask of pipes to select from
* @reason: explanation of why bpp reduction is needed
+ * @reduce_forced_bpp: allow reducing bpps below their forced link bpp
*
* Select the pipe from @pipe_mask with the biggest link bpp value and set the
* maximum of link bpp in @limits below this value. Modeset the selected pipe,
@@ -64,10 +96,11 @@ void intel_link_bw_init_limits(struct intel_atomic_state *state,
* - %-ENOSPC if no pipe can further reduce its link bpp
* - Other negative error, if modesetting the selected pipe failed
*/
-int intel_link_bw_reduce_bpp(struct intel_atomic_state *state,
- struct intel_link_bw_limits *limits,
- u8 pipe_mask,
- const char *reason)
+static int __intel_link_bw_reduce_bpp(struct intel_atomic_state *state,
+ struct intel_link_bw_limits *limits,
+ u8 pipe_mask,
+ const char *reason,
+ bool reduce_forced_bpp)
{
struct intel_display *display = to_intel_display(state);
enum pipe max_bpp_pipe = INVALID_PIPE;
@@ -97,6 +130,10 @@ int intel_link_bw_reduce_bpp(struct intel_atomic_state *state,
*/
link_bpp_x16 = fxp_q4_from_int(crtc_state->pipe_bpp);
+ if (!reduce_forced_bpp &&
+ link_bpp_x16 <= get_forced_link_bpp_x16(state, crtc))
+ continue;
+
if (link_bpp_x16 > max_bpp_x16) {
max_bpp_x16 = link_bpp_x16;
max_bpp_pipe = crtc->pipe;
@@ -112,6 +149,21 @@ int intel_link_bw_reduce_bpp(struct intel_atomic_state *state,
BIT(max_bpp_pipe));
}
+int intel_link_bw_reduce_bpp(struct intel_atomic_state *state,
+ struct intel_link_bw_limits *limits,
+ u8 pipe_mask,
+ const char *reason)
+{
+ int ret;
+
+ /* Try to keep any forced link BPP. */
+ ret = __intel_link_bw_reduce_bpp(state, limits, pipe_mask, reason, false);
+ if (ret == -ENOSPC)
+ ret = __intel_link_bw_reduce_bpp(state, limits, pipe_mask, reason, true);
+
+ return ret;
+}
+
/**
* intel_link_bw_set_bpp_limit_for_pipe - set link bpp limit for a pipe to its minimum
* @state: atomic state
@@ -245,3 +297,141 @@ int intel_link_bw_atomic_check(struct intel_atomic_state *state,
return -EAGAIN;
}
+
+static int force_link_bpp_show(struct seq_file *m, void *data)
+{
+ struct intel_connector *connector = m->private;
+
+ seq_printf(m, FXP_Q4_FMT "\n", FXP_Q4_ARGS(connector->link.force_bpp_x16));
+
+ return 0;
+}
+
+static int str_to_fxp_q4_uint(const char *str, int *val_x16)
+{
+ unsigned int val;
+ int err;
+
+ err = kstrtouint(str, 10, &val);
+ if (err)
+ return err;
+
+ if (val > INT_MAX >> 4)
+ return -ERANGE;
+
+ *val_x16 = fxp_q4_from_int(val);
+
+ return 0;
+}
+
+/* modifies str */
+static int str_to_fxp_q4(char *str, int *val_x16)
+{
+ const char *int_str;
+ char *frac_str;
+ int frac_val;
+ int err;
+
+ int_str = strim(str);
+ frac_str = strchr(int_str, '.');
+
+ if (frac_str)
+ *frac_str++ = '\0';
+
+ err = str_to_fxp_q4_uint(int_str, val_x16);
+ if (err)
+ return err;
+
+ if (!frac_str)
+ return 0;
+
+ if (*frac_str == '+') /* otherwise valid in front of an unsigned integer */
+ return -EINVAL;
+
+ err = str_to_fxp_q4_uint(frac_str, &frac_val);
+ if (err)
+ return err;
+
+ *val_x16 += DIV_ROUND_CLOSEST(frac_val, int_pow(10, strlen(frac_str)));
+
+ return 0;
+}
+
+static int user_str_to_fxp_q4(const char __user *ubuf, size_t len, int *val_x16)
+{
+ char *kbuf;
+ int err;
+
+ kbuf = memdup_user_nul(ubuf, len);
+ if (IS_ERR(kbuf))
+ return PTR_ERR(kbuf);
+
+ err = str_to_fxp_q4(kbuf, val_x16);
+
+ kfree(kbuf);
+
+ return err;
+}
+
+static bool connector_supports_dsc(struct intel_connector *connector)
+{
+ struct intel_display *display = to_intel_display(connector);
+
+ switch (connector->base.connector_type) {
+ case DRM_MODE_CONNECTOR_eDP:
+ return intel_dp_has_dsc(connector);
+ case DRM_MODE_CONNECTOR_DisplayPort:
+ if (connector->mst.dp)
+ return HAS_DSC_MST(display);
+
+ return HAS_DSC(display);
+ default:
+ return false;
+ }
+}
+
+static ssize_t
+force_link_bpp_write(struct file *file, const char __user *ubuf, size_t len, loff_t *offp)
+{
+ struct seq_file *m = file->private_data;
+ struct intel_connector *connector = m->private;
+ struct intel_display *display = to_intel_display(connector);
+ int min_bpp;
+ int bpp_x16;
+ int err;
+
+ err = user_str_to_fxp_q4(ubuf, len, &bpp_x16);
+ if (err)
+ return err;
+
+ if (connector_supports_dsc(connector))
+ min_bpp = intel_dp_dsc_min_src_compressed_bpp();
+ else
+ min_bpp = intel_display_min_pipe_bpp();
+
+ if (bpp_x16 &&
+ (bpp_x16 < fxp_q4_from_int(min_bpp) ||
+ bpp_x16 > fxp_q4_from_int(intel_display_max_pipe_bpp(display))))
+ return -EINVAL;
+
+ err = drm_modeset_lock_single_interruptible(&display->drm->mode_config.connection_mutex);
+ if (err)
+ return err;
+
+ connector->link.force_bpp_x16 = bpp_x16;
+
+ drm_modeset_unlock(&display->drm->mode_config.connection_mutex);
+
+ *offp += len;
+
+ return len;
+}
+DEFINE_SHOW_STORE_ATTRIBUTE(force_link_bpp);
+
+void intel_link_bw_connector_debugfs_add(struct intel_connector *connector)
+{
+ struct dentry *root = connector->base.debugfs_entry;
+
+ debugfs_create_file("i915_force_link_bpp", 0644, root,
+ connector, &force_link_bpp_fops);
+}
@@ -11,6 +11,7 @@
#include "intel_display_limits.h"
struct intel_atomic_state;
+struct intel_connector;
struct intel_crtc_state;
struct intel_link_bw_limits {
@@ -32,5 +33,6 @@ bool intel_link_bw_set_bpp_limit_for_pipe(struct intel_atomic_state *state,
enum pipe pipe);
int intel_link_bw_atomic_check(struct intel_atomic_state *state,
struct intel_link_bw_limits *new_limits);
+void intel_link_bw_connector_debugfs_add(struct intel_connector *connector);
#endif
Add support for forcing the link bpp on a connector via a connector debugfs entry. During reducing link bpps due to a link BW limit, keep bpps close to their forced value. Signed-off-by: Imre Deak <imre.deak@intel.com> --- .../drm/i915/display/intel_display_types.h | 4 + drivers/gpu/drm/i915/display/intel_link_bw.c | 204 +++++++++++++++++- drivers/gpu/drm/i915/display/intel_link_bw.h | 2 + 3 files changed, 203 insertions(+), 7 deletions(-)