[PATCH 4.19 211/211] drm/amd/display: Restore backlight brightness after system resume

[Greg Kroah-Hartman]

From: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>

commit bb264220d9316f6bd7c1fd84b8da398c93912931 upstream.

Laptops with AMD APU doesn't restore display backlight brightness after
system resume.

This issue started when DC was introduced.

Let's use BL_CORE_SUSPENDRESUME so the backlight core calls
update_status callback after system resume to restore the backlight
level.

Tested on Dell Inspiron 3180 (Stoney Ridge) and Dell Latitude 5495
(Raven Ridge).

Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -1462,6 +1462,7 @@ static int amdgpu_dm_backlight_get_brigh
 }
 
 static const struct backlight_ops amdgpu_dm_backlight_ops = {
+	.options = BL_CORE_SUSPENDRESUME,
 	.get_brightness = amdgpu_dm_backlight_get_brightness,
 	.update_status	= amdgpu_dm_backlight_update_status,
 };