NVIDIA driver issue causing backlight problems on ASUS ROG GL503VS running Ubuntu Server 22.04.4 LTS

Hi everyone! I’m running into an issue with NVIDIA drivers (version 550.54.15) that does not occur when using the built-in open-source Nouveau driver on my ASUS ROG GL503VS (SCAR Edition) running Ubuntu Server 22.04.4 LTS (GNU/Linux 5.15.0-105-generic x86_64), and so far, I have not been able to find a way to resolve it.
More specifically, I believe it’s not just the brightness but a lot of things might be broken under the hood (like the eDP-1 output which is showing as “disabled” while it’s actually not, which is also verifiable when Nouveau is used), and changing driver versions, switching between distro, third-party, and NVIDIA legacy kernel module does not seem to improve the situation at all.
It’s not a huge issue, but it’s quite annoying that when 1 is set to /sys/class/graphics/fb0/blank or any value is set to /sys/class/backlight/nvidia_0/brightness, nothing changes about the backlight brightness. The console does blank in the former case, but the screen stays at full brightness and refuses to turn off.
I tried using grub to set eDP-1:d (which is not a smart thing to do, I know…) but that also didn’t turn off the display (in fact it seemed to have no effect at all), and so I’m stuck with a constantly-lit screen at full brightness.
I’d like to do some ML activities on the thing, so using Nouveau instead is basically out of the picture (unless I could figure out a way to make CUDA work with it, which also seems impossible), so any help on how to resolve this issue would be greatly appreciated.

Actually, there already seems to be a similar topic posted last year and nobody has responded yet…

Since there’s no update, I’d assume the problem persists for that user as well which is a bit sad. I’d be very happy to provide additional information if required, though I mainly use it remotely so SSH is what’s usually preferred.
Many thanks in advance to anyone helping to look into the issue!

Attached here is the bug report: nvidia-bug-report.log.gz (323.0 KB)
Hopefully this information could be of help…

Upon searching for “backlight”, it seems like it is indeed trying to restore the brightness value:

ubuntu systemd[1]: systemd-backlight@backlight:nvidia_0.service: Found ordering cycle on nvidia-persistenced.service/start

Except that only the value is restored but the actual screen’s brightness is not changing at all.

Also, something I’ve noticed is that with the nouveau driver, the max_brightness goes up to 255 but when NVIDIA driver is installed it only goes up to 100.
Not sure if this is hardware-dependent or driver-dependent though…

We are tracking this in internal bug 4093302. We have a potential fix implemented.

Hi there!
Thank you very much for the update! I’m glad this issue could potentially be fixed now.
Unfortunately for the laptop, the screen kind of blew up (not physically, but it’s not displaying stuff properly anymore, which I’ve nailed down to likely a hardware issue), and it was probably this that caused it… I’m not sure what settings it was locking the screen at, but it turns out this could actually cause some real damage (to be fair, it’s expected to a level, I just didn’t anticipate it to be this fast, sigh).
I’ll try connecting external displays and stuff when I gain physical access to the machine again, but I probably won’t be able to test the fix anymore, since the internal display is pretty much dead.
Again, I really appreciate the efforts!