This is a note to let you know that I've just added the patch titled
drm/amd/display: Reinstate LFC optimization
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-amd-display-reinstate-lfc-optimization.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit d512d34f9e44e5fa0b0823bbaed7c2ae422321c5
Author: Amanda Liu <amanda.liu@xxxxxxx>
Date: Thu Nov 21 16:06:57 2019 -0500
drm/amd/display: Reinstate LFC optimization
[ Upstream commit ded6119e825aaf0bfc7f2a578b549d610da852a7 ]
[why]
We want to streamline the calculations made when entering LFC.
Previously, the optimizations led to screen tearing and were backed out
to unblock development.
[how]
Integrate other calculations parameters, as well as screen tearing,
fixes with the original LFC calculation optimizations.
Signed-off-by: Amanda Liu <amanda.liu@xxxxxxx>
Reviewed-by: Aric Cyr <Aric.Cyr@xxxxxxx>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Stable-dep-of: 07e388aab042 ("drm/amd/display: prevent potential division by zero errors")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/amd/display/modules/freesync/freesync.c b/drivers/gpu/drm/amd/display/modules/freesync/freesync.c
index 7d67cb2c61f04..dbbd7d2765ea5 100644
--- a/drivers/gpu/drm/amd/display/modules/freesync/freesync.c
+++ b/drivers/gpu/drm/amd/display/modules/freesync/freesync.c
@@ -37,8 +37,8 @@
#define STATIC_SCREEN_RAMP_DELTA_REFRESH_RATE_PER_FRAME ((1000 / 60) * 65)
/* Number of elements in the render times cache array */
#define RENDER_TIMES_MAX_COUNT 10
-/* Threshold to exit BTR (to avoid frequent enter-exits at the lower limit) */
-#define BTR_EXIT_MARGIN 2000
+/* Threshold to exit/exit BTR (to avoid frequent enter-exits at the lower limit) */
+#define BTR_MAX_MARGIN 2500
/* Threshold to change BTR multiplier (to avoid frequent changes) */
#define BTR_DRIFT_MARGIN 2000
/*Threshold to exit fixed refresh rate*/
@@ -250,24 +250,22 @@ static void apply_below_the_range(struct core_freesync *core_freesync,
unsigned int delta_from_mid_point_in_us_1 = 0xFFFFFFFF;
unsigned int delta_from_mid_point_in_us_2 = 0xFFFFFFFF;
unsigned int frames_to_insert = 0;
- unsigned int min_frame_duration_in_ns = 0;
- unsigned int max_render_time_in_us = in_out_vrr->max_duration_in_us;
unsigned int delta_from_mid_point_delta_in_us;
-
- min_frame_duration_in_ns = ((unsigned int) (div64_u64(
- (1000000000ULL * 1000000),
- in_out_vrr->max_refresh_in_uhz)));
+ unsigned int max_render_time_in_us =
+ in_out_vrr->max_duration_in_us - in_out_vrr->btr.margin_in_us;
/* Program BTR */
- if (last_render_time_in_us + BTR_EXIT_MARGIN < max_render_time_in_us) {
+ if ((last_render_time_in_us + in_out_vrr->btr.margin_in_us / 2) < max_render_time_in_us) {
/* Exit Below the Range */
if (in_out_vrr->btr.btr_active) {
in_out_vrr->btr.frame_counter = 0;
in_out_vrr->btr.btr_active = false;
}
- } else if (last_render_time_in_us > max_render_time_in_us) {
+ } else if (last_render_time_in_us > (max_render_time_in_us + in_out_vrr->btr.margin_in_us / 2)) {
/* Enter Below the Range */
- in_out_vrr->btr.btr_active = true;
+ if (!in_out_vrr->btr.btr_active) {
+ in_out_vrr->btr.btr_active = true;
+ }
}
/* BTR set to "not active" so disengage */
@@ -323,7 +321,9 @@ static void apply_below_the_range(struct core_freesync *core_freesync,
/* Choose number of frames to insert based on how close it
* can get to the mid point of the variable range.
*/
- if (delta_from_mid_point_in_us_1 < delta_from_mid_point_in_us_2) {
+ if ((frame_time_in_us / mid_point_frames_ceil) > in_out_vrr->min_duration_in_us &&
+ (delta_from_mid_point_in_us_1 < delta_from_mid_point_in_us_2 ||
+ mid_point_frames_floor < 2)) {
frames_to_insert = mid_point_frames_ceil;
delta_from_mid_point_delta_in_us = delta_from_mid_point_in_us_2 -
delta_from_mid_point_in_us_1;
@@ -339,7 +339,7 @@ static void apply_below_the_range(struct core_freesync *core_freesync,
if (in_out_vrr->btr.frames_to_insert != 0 &&
delta_from_mid_point_delta_in_us < BTR_DRIFT_MARGIN) {
if (((last_render_time_in_us / in_out_vrr->btr.frames_to_insert) <
- in_out_vrr->max_duration_in_us) &&
+ max_render_time_in_us) &&
((last_render_time_in_us / in_out_vrr->btr.frames_to_insert) >
in_out_vrr->min_duration_in_us))
frames_to_insert = in_out_vrr->btr.frames_to_insert;
@@ -792,6 +792,11 @@ void mod_freesync_build_vrr_params(struct mod_freesync *mod_freesync,
refresh_range = in_out_vrr->max_refresh_in_uhz -
in_out_vrr->min_refresh_in_uhz;
+ in_out_vrr->btr.margin_in_us = in_out_vrr->max_duration_in_us -
+ 2 * in_out_vrr->min_duration_in_us;
+ if (in_out_vrr->btr.margin_in_us > BTR_MAX_MARGIN)
+ in_out_vrr->btr.margin_in_us = BTR_MAX_MARGIN;
+
in_out_vrr->supported = true;
}
@@ -808,6 +813,7 @@ void mod_freesync_build_vrr_params(struct mod_freesync *mod_freesync,
in_out_vrr->btr.inserted_duration_in_us = 0;
in_out_vrr->btr.frames_to_insert = 0;
in_out_vrr->btr.frame_counter = 0;
+
in_out_vrr->btr.mid_point_in_us =
(in_out_vrr->min_duration_in_us +
in_out_vrr->max_duration_in_us) / 2;
diff --git a/drivers/gpu/drm/amd/display/modules/inc/mod_freesync.h b/drivers/gpu/drm/amd/display/modules/inc/mod_freesync.h
index dc187844d10b1..dbe7835aabcf7 100644
--- a/drivers/gpu/drm/amd/display/modules/inc/mod_freesync.h
+++ b/drivers/gpu/drm/amd/display/modules/inc/mod_freesync.h
@@ -92,6 +92,7 @@ struct mod_vrr_params_btr {
uint32_t inserted_duration_in_us;
uint32_t frames_to_insert;
uint32_t frame_counter;
+ uint32_t margin_in_us;
};
struct mod_vrr_params_fixed_refresh {
