Ubuntu brightness setting not actually changing brightness on laptop screen

Dawnraider00 · October 17, 2020

I have an Asus G752VT laptop that I installed ubuntu on. The screen is stuck on max brightness, but the function keys for brightness and the actual OS settings for screen brightness work. Everything I've found online has been related to getting the software side working but for me it is the hardware that is not responding to the software changes. (e.g /sys/class/brightness/acpi_video0/brightness DOES respond to brightness keys) How can I fix this?

BobVonBob · October 17, 2020

You can try these changes.

https://askubuntu.com/questions/1049681/ubuntu-18-04-cannot-change-display-brightness-or-wake-from-sleep-on-asus-rog-lap

Dawnraider00 · October 17, 2020

That isn't the same issue as I am having. The function keys DO work on my laptop, it's the screen itself that does not respond to the changes. The brightness setting is getting updated, just the screen does not respect the setting. I had already tried those changes before anyways.

BobVonBob · October 18, 2020

2 hours ago, Dawnraider00 said:

That isn't the same issue as I am having. The function keys DO work on my laptop, it's the screen itself that does not respond to the changes. The brightness setting is getting updated, just the screen does not respect the setting. I had already tried those changes before anyways.

I suspect it is the same issue, but the asker/answerer described it in a different way. Their problem wasn't that the function keys didn't work, just like yours isn't, but that the function keys for brightness didn't adjust the screen's brightness, just like yours aren't.

Alternatively you can try this, but try the other solution first. It's a significantly more elegant solution if it solves your problem.

https://askubuntu.com/questions/1045624/how-to-switch-between-options-in-sys-class-backlight-to-solve-brightness-prob/1045763#1045763

Dawnraider00 · October 18, 2020

I had tried what was in the previous link you posted without any effect. The second link does seem to be exactly what I needed but I do not have any nv_backlight folder in /sys/class/backlight, all I have is acpi_video0 and acpi_video1, neither of which actually have any effect on the brightness. Anything I looked up for how to get nv_backlight there didn't come up with anything because basically everything I could find was related to the backlight issue but already assumed it was there. Other things have also mentioned gmux_brightness, but I do not have that folder either. I just updated nvidia drivers too to double check without success.