[PATCH 07/17] drm/amd/display: Fix brightness level not retained over reboot

[Zaeem Mohamed]

From: Tom Chung <chiahsuan.ch...@amd.com>

[Why]
During boot up and resume the DC layer will reset the panel
brightness to fix a flicker issue.

It will cause the dm->actual_brightness is not the current panel
brightness level. (the dm->brightness is the correct panel level)

[How]
Set the backlight level after do the set mode.

Reviewed-by: Sun peng Li <sunpeng...@amd.com>
Signed-off-by: Tom Chung <chiahsuan.ch...@amd.com>
Signed-off-by: Zaeem Mohamed <zaeem.moha...@amd.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c 
b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index bbfc47f6595f..2599a99509de 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -9411,6 +9411,7 @@ static void amdgpu_dm_commit_streams(struct 
drm_atomic_state *state,
        bool mode_set_reset_required = false;
        u32 i;
        struct dc_commit_streams_params params = {dc_state->streams, 
dc_state->stream_count};
+       bool set_backlight_level = false;
 
        /* Disable writeback */
        for_each_old_connector_in_state(state, connector, old_con_state, i) {
@@ -9530,6 +9531,7 @@ static void amdgpu_dm_commit_streams(struct 
drm_atomic_state *state,
                        acrtc->hw_mode = new_crtc_state->mode;
                        crtc->hwmode = new_crtc_state->mode;
                        mode_set_reset_required = true;
+                       set_backlight_level = true;
                } else if (modereset_required(new_crtc_state)) {
                        drm_dbg_atomic(dev,
                                       "Atomic commit: RESET. crtc id 
%d:[%p]\n",
@@ -9581,6 +9583,19 @@ static void amdgpu_dm_commit_streams(struct 
drm_atomic_state *state,
                                acrtc->otg_inst = status->primary_otg_inst;
                }
        }
+
+       /* During boot up and resume the DC layer will reset the panel 
brightness
+        * to fix a flicker issue.
+        * It will cause the dm->actual_brightness is not the current panel 
brightness
+        * level. (the dm->brightness is the correct panel level)
+        * So we set the backlight level with dm->brightness value after set 
mode
+        */
+       if (set_backlight_level) {
+               for (i = 0; i < dm->num_of_edps; i++) {
+                       if (dm->backlight_dev[i])
+                               amdgpu_dm_backlight_set_level(dm, i, 
dm->brightness[i]);
+               }
+       }
 }
 
 static void dm_set_writeback(struct amdgpu_display_manager *dm,
-- 
2.34.1