drm/amd/display: Freesync does not engage on some displays

[Why]
Current render margin time is not sufficient to compute exit frame
time for most monitors.

[How]
Declared  render margin in FPS to compute a exit frame rate that is
4 FPS above the minimum FPS required to engage FreeSync.
 Also did code clean-up to remove redundancies.

Signed-off-by: Harmanprit Tatla <htatla@amd.com>
Reviewed-by: Anthony Koo <Anthony.Koo@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 9 insertions, 28 deletions

diff --git a/drivers/gpu/drm/amd/display/modules/freesync/freesync.c b/drivers/gpu/drm/amd/display/modules/freesync/freesync.c
index 4018c7180d00..620a171620ee 100644
--- a/drivers/gpu/drm/amd/display/modules/freesync/freesync.c
+++ b/drivers/gpu/drm/amd/display/modules/freesync/freesync.c
@@ -37,6 +37,8 @@
 #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 fixed refresh rate*/
+#define FIXED_REFRESH_EXIT_MARGIN_IN_HZ 4
 /* Number of consecutive frames to check before entering/exiting fixed refresh*/
 #define FIXED_REFRESH_ENTER_FRAME_COUNT 5
 #define FIXED_REFRESH_EXIT_FRAME_COUNT 5
@@ -257,40 +259,14 @@ static void apply_below_the_range(struct core_freesync *core_freesync,
                 if (in_out_vrr->btr.btr_active) {
                         in_out_vrr->btr.frame_counter = 0;
                         in_out_vrr->btr.btr_active = false;
-
-                /* Exit Fixed Refresh mode */
-                } else if (in_out_vrr->fixed.fixed_active) {
-
-                        in_out_vrr->fixed.frame_counter++;
-
-                        if (in_out_vrr->fixed.frame_counter >
-                                        FIXED_REFRESH_EXIT_FRAME_COUNT) {
-                                in_out_vrr->fixed.frame_counter = 0;
-                                in_out_vrr->fixed.fixed_active = false;
-                        }
                 }
         } else if (last_render_time_in_us > max_render_time_in_us) {
                 /* Enter Below the Range */
-                if (!in_out_vrr->btr.btr_active &&
-                                in_out_vrr->btr.btr_enabled) {
-                        in_out_vrr->btr.btr_active = true;
-
-                /* Enter Fixed Refresh mode */
-                } else if (!in_out_vrr->fixed.fixed_active &&
-                                !in_out_vrr->btr.btr_enabled) {
-                        in_out_vrr->fixed.frame_counter++;
-
-                        if (in_out_vrr->fixed.frame_counter >
-                                        FIXED_REFRESH_ENTER_FRAME_COUNT) {
-                                in_out_vrr->fixed.frame_counter = 0;
-                                in_out_vrr->fixed.fixed_active = true;
-                        }
-                }
+                in_out_vrr->btr.btr_active = true;
         }
 
         /* BTR set to "not active" so disengage */
         if (!in_out_vrr->btr.btr_active) {
-                in_out_vrr->btr.btr_active = false;
                 in_out_vrr->btr.inserted_duration_in_us = 0;
                 in_out_vrr->btr.frames_to_insert = 0;
                 in_out_vrr->btr.frame_counter = 0;
@@ -375,7 +351,12 @@ static void apply_fixed_refresh(struct core_freesync *core_freesync,
         bool update = false;
         unsigned int max_render_time_in_us = in_out_vrr->max_duration_in_us;
 
-        if (last_render_time_in_us + BTR_EXIT_MARGIN < max_render_time_in_us) {
+        //Compute the exit refresh rate and exit frame duration
+        unsigned int exit_refresh_rate_in_milli_hz = ((1000000000/max_render_time_in_us)
+                        + (1000*FIXED_REFRESH_EXIT_MARGIN_IN_HZ));
+        unsigned int exit_frame_duration_in_us = 1000000000/exit_refresh_rate_in_milli_hz;
+
+        if (last_render_time_in_us < exit_frame_duration_in_us) {
                 /* Exit Fixed Refresh mode */
                 if (in_out_vrr->fixed.fixed_active) {
                         in_out_vrr->fixed.frame_counter++;