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
