Adding some display people. On Wed, May 20, 2020 at 5:46 PM Alexander Monakov <amonakov@xxxxxxxxx> wrote: > > Hello, > > I have a laptop with the recent Renoir SoC. Screen brightness is > controlled via the amdgpu driver. Unfortunately it doesn't work > properly: brightness doesn't go below a certain threshold. In one > experiment I've found the threshold to be about 95 (of 255), which is > quite high. > > There's a bugreport on the tracker from a person with the same laptop > model as mine that says that the threshold may vary from boot to boot. > > So far I was able to find a workaround: avoiding > dmcu_set_backlight_level like in the patch below gives more reliable > backlight control (but at the expense of breaking "actual_brightness" > sysfs file, because it reads from DMCU registers). > > What might be the problem and can I help investigate this further? Would > really like to see this work properly. > > Alexander > > diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c b/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c > index b8a3fc505c9b..3274b0d15893 100644 > --- a/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c > +++ b/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c > @@ -428,7 +428,7 @@ static bool dce_abm_set_backlight_level_pwm( > backlight_pwm_u16_16, backlight_pwm_u16_16); > > /* If DMCU is in reset state, DMCU is uninitialized */ > - if (use_smooth_brightness) > + if (0 && use_smooth_brightness) > dmcu_set_backlight_level(abm_dce, > backlight_pwm_u16_16, > frame_ramp, > _______________________________________________ > amd-gfx mailing list > amd-gfx@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/amd-gfx _______________________________________________ amd-gfx mailing list amd-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/amd-gfx
