I use HP EliteBook 745 G5 with Ryzen 5 PRO 2500U.
Starting with the:
commit 262485a50fd4532a8d71165190adc7a0a19bcc9e (refs/bisect/bad)
Author: Anthony Koo <Anthony.=
Koo@amd.com>
Date: Fri Oct 12 21:34:32 2018 -0400
drm/amd/display: Expand dc to use 16.16 bit backlight
[Why] We want to increase precision for backlight setting.
But DC interface takes 8 bit backlight level value only.
[How] DMCU already takes 16 bit backlight level.
Expand the DC interface to take 16.16 bit value.
Max 32 bit backlight value (0xFFFF) will represent
max backlight (100%)
Signed-off-by: Anthony Koo <Anthony.Koo@amd.com>
Reviewed-by: Tony Cheng <T=
ony.Cheng@amd.com>
Acked-by: Leo Li <sunpeng.=
li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
After resume from RAM my notebook display is all black.
Before suspend:
> cat /sys/class/backlight/amdgpu_bl0/{actual_brig=
htness,brightness}
65535
255
After resume:
> cat /sys/class/backlight/amdgpu_bl0/{actual_brig=
htness,brightness}
0
255
This can be workarounded by:
echo 255 > /sys/class/backlight/amdgpu_bl0/brightness
assuming one can execute that without a working display.
This problem still exists in the 5.0.0-rc2.