Score:1

Full brightness on startup after the recent update

cn flag

After every reboot, my laptop, on startup is on with 100% brightness. I have to manually turn it down using the function keys everytime. Generally, the default start-up brightness used to be around 20% which too I had used to turn down, but now after a recent update it has reached to 100% on its own.

My other laptop running the same version is still at 20% default start-up brightness. I know there can be user made scripts that will automatically turn down the brightness for me on each start-up. But I want to do this natively and permanently from system settings or something.

I'm running Ubuntu 20.04 on a Dell laptop.

ggorlen avatar
cn flag
See also [Brightness is reset to maximum on every restart](https://askubuntu.com/questions/151651/brightness-is-reset-to-maximum-on-every-restart)
in flag
Could you [edit] your question to include the brand and model of your computer? The solutions for this issue are generally manufacturer-specific
heynnema avatar
ru flag
Status please...
Score:0
ru flag

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

Score:0
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