Failed to save backlight issue on boot

Issues & Assistance Newbies
1

Hello people, whenever I boot I get two error messages

[FAILED] Failed to start Load/Save Screen Backlight Brightness of backlight:acpi_video0

&

[FAILED] Failed to start Load/Save Screen Backlight #tness of backlight:amdgpu_bl0

My system configurations are:
AMD Ryzen 5 4600H
15.1GB RAM
GTX 1660 Ti, AMD RENOIR

I am attaching the output of mhwd command

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3

This is a known kernel bug for AMD backlight.
Check if you really have "two backlight services", or (normally) only amdgpu_bl0

ls /sys/class/backlight/

Check what systemd finds out

systemctl status systemd-backlight@*

Even if there are two, mask acpi_video0, to test if your system hardware buttons (assuming a laptop, or a capable keyboard, or shortcuts) can control display backlight.

systemctl is-enabled systemd-backlight@backlight:acpi_video0.service
"expected output"> static
sudo systemctl mask systemd-backlight@backlight:acpi_video0.service

Until kernel AMD bug is fixed, set kernel param in /etc/default/grub (update grub afterwards, of course)

systemd.restore_state=0

Please, post your results.
PS: I have an AMD Ryzen laptop, not AMD/Nvidia, so your results may differ.

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4

hi, sorry for the late reply.

I executed these commands and here are the results

ls /sys/class/backlight/
amdgpu_bl0

systemctl is-enabled systemd-backlight@backlight:acpi_video0.service
static

sudo systemctl mask systemd-backlight@backlight:acpi_video0.service
Created symlink /etc/systemd/system/systemd-backlight@backlight:acpi_video0.service → /dev/null.

after opening /etc/default/grub in micro where am i supposed to add

systemd.restore_state=0

thank you

edit: i added this on GRUB_CMDLINE_LINUX_DEFAULT= and upon rebooting didn’t face those error.
thanks although brightness still isn’t saved

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Glad that helped you.

Very nice to have you helping out on the forum @petsam, so nice to see you back in on the action. :smiley:

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That’s why we call it a bug :wink:.
The brightness values of Linux “kernel” and AMD “GPU” are of different scale, so 255 and 65000 are for 100%, for each case (numbers are from memory and maybe a little different).
With the current workaround, you just use one scale (0-255).
Check your settings with

find  /sys/class/backlight/amdgpu_bl0/*brightness -type f -printf %f  -exec cat {} \;
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7

I have this bug on every distro :slight_smile:

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I still got the error but my linux still boots up not like my earlier install where I get stuck so I had to reinstall garuda dr460nized again in hopes that this was because installing rog-core. But at least it still boots up and I'm really hoping this will be fixed soon. :smiley:

EDIT: Nvm, fixed it. :smiley:

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A post was split to a new topic: Problem with backlight gmux_backlight

10

So what was final solution? I’m also having exact same problem, my desktop environment is not loading, error is also not showing only my mouse cursor shows… And if I press ctrl+alt+F1 then the error shows like failed to save…

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This thread is extremely old; please no necro-bumping.

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