Score:0

Screen brightness goes to 10-15% when charger plugs

do flag

I have Ubuntu 21.10 installed on Lenovo Ideapad Gaming 3 with Ryzen 4600H and GTX1650. The screen brightness have several problems with user interface. First one is after the reboot or turning on the device, the actual brightness doesn't match the menu brightness field in top right corner. The menu shows 0 but the actual is 100%. The next problem is if i plug (or unplug) the charger for the first time after the boot, the brightness goes to 20 out of 255 (maximum brightness in amdgpu_bl0 in /sys directory) which is super annoying for me because i have to set it back manually. I guess the problem is GNOME problem. What should i do to fix those?

ChanganAuto avatar
us flag
It's a mix of software interacting with that specific hardware (Ryzen). There is no fix.
heynnema avatar
ru flag
@ChanganAuto It's a possible Ubuntu bug. See my answer.
heynnema avatar
ru flag
Please see my answer. If it's helpful, please remember to accept it by clicking on the checkmark icon that appears just to the left of my answer. Thanks!
heynnema avatar
ru flag
Status please...
Score:1
ru flag

Note: This should take care of some/all of your problem...

The problem is that there's a process that runs at boot, and also at shutdown, that tries to restore/save backlight settings. One some configurations the restore happens incorrectly, and can cause the brightness problem that you see. Here we will add a minor kernel option so that this process doesn't restore an invalid brightness setting.

man systemd-backlight

Rather than using the script that you found, (that I probably wrote), do this:

Edit /etc/default/grub:

sudo -H gedit /etc/default/grub

Locate the line that looks like:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

And change it to:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash systemd.restore_state=0"

sudo update-grub

Set your brightness to the desired level.

reboot

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