[PATCH] drm/amd/display: Fix programming backlight on OLED panels

[Mario Limonciello]

From: Mario Limonciello <mario.limonciello at amd.com>

commit 38077562e0594 ("drm/amd/display: Implement new
backlight_level_params structure") adjusted DC core to require
the backlight type to be programmed in the dc link when changing
brightness.  This isn't initialized in amdgpu_dm for OLED panels
though which broke brightness.

Explicitly initialize when aux support is enabled.

Reported-and-tested-by: Luke Jones <luke at ljones.dev>
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3792
Fixes: 38077562e059 ("drm/amd/display: Implement new backlight_level_params structure")
Signed-off-by: Mario Limonciello <mario.limonciello at amd.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 2 ++
 1 file changed, 2 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 19a58630e7740..243cee2841312 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -3483,6 +3483,8 @@ static void update_connector_ext_caps(struct amdgpu_dm_connector *aconnector)
 		caps->aux_support = false;
 	else if (amdgpu_backlight == 1)
 		caps->aux_support = true;
+	if (caps->aux_support)
+		aconnector->dc_link->backlight_control_type = BACKLIGHT_CONTROL_AMD_AUX;
 
 	luminance_range = &conn_base->display_info.luminance_range;
 
-- 
2.43.0