I tried Ubuntu Mate 19.10 live on my testing system (AMD Ryzen 5 2500U with Radeon Vega Graphics - seems to be the same AMD CPU on your Acer), and brightness control works without any problems even though actual_brightness has a fixed and higher value.
The below is the latest function can be ftrace'd before setting brightness on my AMD platform. https://github.com/torvalds/linux/blob/master/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c#L418 See result of using kprobe-perf (needs to be installed) with writing max (255) to brightness $ sudo kprobe-perf 'p:dce_abm_set_backlight_level_pwm $arg1 $arg2 $arg3 $arg4 $arg5 ' Tracing kprobe dce_abm_set_backlight_level_pwm. Ctrl-C to end. tee-2074 [001] .... 1009.569878: dce_abm_set_backlight_level_pwm: (dce_abm_set_backlight_level_pwm+0x0/0x410 [amdgpu]) arg1=0xffff9874e0928900 arg2=0xffff arg3=0x0 arg4=0x0 arg5=0x0 Note the arg2 = 0xffff (max brightness) and arg5 = 0 (no "use_smooth_brightness") If you observe the same behaiours but different results, the Acer hardware may have something special that needs attention either from Acer or from AMD... -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1861925 Title: BrightnessOutofRange: Actual brightness for amdgpu_bl0 not in range 0..255 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1861925/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
