Guide: How to fix brightness issues after suspend on Ubuntu-based distros

Hardware Librem 14
1

I use Zorin, which is based on Ubuntu, and without a couple of tweaks the brightness will be dim after resuming from sleep, and the brightness keys won’t work at all after resuming from suspend.

I wanted to share how I fix this after a new install.

First, install the EC module from Purism, which fixes the button issues after suspend:
sudo apt install librem-ec-acpi-dkms

Then, sudo vim /etc/default/gruband add acpi_backlight=native to GRUB_CMDLINE_LINUX_DEFAULT:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=native"

Run sudo update-grub and restart. (Consider backing up the /etc/default/grub file first.)

This fixes the issue with the brightness being low after sleep.

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I don’t know about sleep, but happens to me after almost daily updates.

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If you put it in /etc/default/grub then the change should survive most updates.

(Only kernel and other low level updates are even relevant. I mean an update to e.g. Firefox or some GNOME application won’t touch GRUB. But an update that does impact GRUB e.g. a new software version of GRUB, will regenerate the GRUB environment and pick up the defaults from the above file. The only time you will have a problem is if an update provides a new version of
/etc/default/grub, which ideally would only be release upgrades e.g. byzantium to crimson, if at all.)

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