Comment # 16 on bug 1217750 from varval761

I tried setting nvidia.NVreg_RegistryDwords=EnableBrightnessControl=1 for both
nouveau and nvidia, and behavior didn't change. I also tried setting
amdgpu.backlight=0 alongside this parameter, and no change with that either.

I also tried setting amdgpu.backlight=1 with no other parameters, and no change
either (still only showed nvidia_wmi_ec_backlight).

While testing all these different configurations, I also suspended and resumed,
and no change in behavior with that either.


I also found this thread of info which might be related?
https://lore.kernel.org/all/Y785lBG%2FAIdHBB0C@lenny/ My GPU is indeed the 3050
mobile, but in my BIOS there's only one dropdown to choose between hybrid and
UMA, so I guess my machine doesn't have a proper mux switch? I also checked in
Windows 11's control panel and the Nvidia control panel and both indicate the
display is connected to the AMD GPU.

So, overall, the only thing that's worked so far is acpi_backlight=native,
which switches the device to amdgpu_bl2 which can be changed. But let me know
if there's anything else we should try! (Or if there's a more "proper" fix we
can attempt)