6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Mario Limonciello mario.limonciello@amd.com
commit b5a981e1b34e44f94a5967f730fff4166f2101e8 upstream.
[Why] To avoid flickering during boot default brightness level set by BIOS should be maintained for as much of the boot as feasible. commit 2fe87f54abdc ("drm/amd/display: Set default brightness according to ACPI") attempted to set the right levels for AC vs DC, but brightness still got reset to maximum level in initialization code for setup_backlight_device().
[How] Remove the hardcoded initialization in setup_backlight_device() and instead program brightness value to match BIOS (AC or DC). This avoids a brightness flicker from kernel changing the value. Userspace may however still change it during boot.
Fixes: 2fe87f54abdc ("drm/amd/display: Set default brightness according to ACPI") 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 0747acf3311229e22009bec4a9e7fc30c879e842) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -4822,6 +4822,7 @@ amdgpu_dm_register_backlight_device(stru dm->backlight_dev[aconnector->bl_idx] = backlight_device_register(bl_name, aconnector->base.kdev, dm, &amdgpu_dm_backlight_ops, &props); + dm->brightness[aconnector->bl_idx] = props.brightness;
if (IS_ERR(dm->backlight_dev[aconnector->bl_idx])) { DRM_ERROR("DM: Backlight registration failed!\n"); @@ -4889,7 +4890,6 @@ static void setup_backlight_device(struc aconnector->bl_idx = bl_idx;
amdgpu_dm_update_backlight_caps(dm, bl_idx); - dm->brightness[bl_idx] = AMDGPU_MAX_BL_LEVEL; dm->backlight_link[bl_idx] = link; dm->num_of_edps++;