drm/amd/display: Read back max backlight value at boot

[ Upstream commit 53a53f8687faf492df2644d8c18ff0217fc18730 ]

[Why]
If there is no program explicitly setting the backlight
brightness (for example, during a minimal install of linux), the
hardware defaults to maximum brightness but the backlight_device
defaults to 0 value.  Thus, settings displays the wrong brightness
value.

[How]
When creating the backlight device, set brightness to max

Signed-off-by: David Francis <David.Francis@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
David Francis 2018-07-18 16:03:30 -04:00 committed by Greg Kroah-Hartman
parent 5bd634167f
commit ac5395827d

View File

@ -1334,6 +1334,7 @@ amdgpu_dm_register_backlight_device(struct amdgpu_display_manager *dm)
struct backlight_properties props = { 0 };
props.max_brightness = AMDGPU_MAX_BL_LEVEL;
props.brightness = AMDGPU_MAX_BL_LEVEL;
props.type = BACKLIGHT_RAW;
snprintf(bl_name, sizeof(bl_name), "amdgpu_bl%d",