Brightness control not working on Legion 5 (Ryzen 5800H + RTX 3050 Ti)

Just loaded up Ubuntu 20.04 on this laptop. Everything's working perfectly, except for brightness control.

I've been following all the advice I can over at this thread: Legion 5 pro brightness control doesn't work on ubuntu 20.04 with nvidia driver 460

...but, nothing works for me. I haven't been able to find a single mention of a solution for the specific model I have anywhere on the internet. Again, this is the model with the Ryzen 5800H and RTX 3050 Ti. I'm running official kernel 5.11.0.37.41. I've tried the discrete mode solution on Nvidia proprietary driver version 460 and 470, with the exact same results every time. I've also tried copying my modified xorg.conf to xorg.conf.d/10-nvidia.conf, and that didn't help either. I've tried the suggestion from the Nvidia forum about adding some parameters to initramfs, and it didn't make a difference.

The most progress I've been able to make is booting using the method in the above article for hybrid graphics mode, which led to the display not even turning on after boot.

What's strange about this is that I'm switching here from Manjaro because it was giving me trouble and I'm already comfortable with Ubuntu. On Manjaro, however, the RegistryDword line in xorg.conf was enough on its own to make brightness control work properly. So, I really don't know what I'm doing wrong here.

I haven't tried using the nouveau drivers, but I'd very strongly prefer not to unless absolutely necessary.

Solution 1:

Try an OEM kernel, e.g.:

sudo apt install linux-oem-20.04d