(In reply to Takashi Iwai from comment #42) > The amdgpu.backlight module option was already merged in the upstream, so TW > should have a workaround (passing amdgpu.backlight=0 boot option). This was > also already merged in SLE15-SP3 / Leap 15.3 kernel, too. But I don't think > we'd fix this for Leap 15.2. > > The root cause of the problem hasn't been figured out yet. My bet is that > it's a BIOS bug, and more proper workarounds are needed in AMDGPU driver > side, but this has to be sorted out in the upstream development. Feel free > to join to the upstream gitlab Issues. It seems that without the amdgpu.backlight=0 kernel parameter the brightness control is working in hybrid mode. I don't know what fixed it maybe this https://gitlab.freedesktop.org/agd5f/linux/-/commit/f2ad3accefc63e72e9932e141c21875cc04beec8 commit. But the brightness control seems to work good now in Linux 5.14.14 in TW.