drm/amd/display: Restore correct backlight brightness after a GPU reset

[Why]
GPU reset will attempt to restore cached state, but brightness doesn't
get restored. It will come back at 100% brightness, but userspace thinks
it's the previous value.

[How]
When running resume sequence if GPU is in reset restore brightness
to previous value.

Acked-by: Wayne Lin <Wayne.Lin@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Tom Chung <chiahsuan.chung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 5e19e2b57b6bb640d68dfc7991e1e182922cf867)
Cc: stable@vger.kernel.org

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 4bd7f82c582dcce915af6241dced58fcaa1fd68e..74ad0d1240febc17c7a097ee0f0e4da8ad440db9 100644 (file)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -245,6 +245,10 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev,
 static void handle_hpd_irq_helper(struct amdgpu_dm_connector *aconnector);
 static void handle_hpd_rx_irq(void *param);
 
+static void amdgpu_dm_backlight_set_level(struct amdgpu_display_manager *dm,
+                                        int bl_idx,
+                                        u32 user_brightness);
+
 static bool
 is_timing_unchanged_for_freesync(struct drm_crtc_state *old_crtc_state,
                                 struct drm_crtc_state *new_crtc_state);
@@ -3371,6 +3375,12 @@ static int dm_resume(struct amdgpu_ip_block *ip_block)
 
                mutex_unlock(&dm->dc_lock);
 
+               /* set the backlight after a reset */
+               for (i = 0; i < dm->num_of_edps; i++) {
+                       if (dm->backlight_dev[i])
+                               amdgpu_dm_backlight_set_level(dm, i, dm->brightness[i]);
+               }
+
                return 0;
        }