Issue with backlight not working on login and a working fix.

So for the last 2 months I've had the issue that when my laptop wakes up from suspend the backlight does not start. As I have a solution I will do as @Fabby requested it and post in a new message the solution in this thread.

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:sunglasses: :+1:

Could you do us a favour and mark your own question as "Solution" like this:


so that your question gets removed from the "unsolved" queue and if anyone else has the same question as you and they look for a solution, they'll find it as well!

If that would be impossible, cut the solution from your question and paste it below this one and then mark that one as "solution".

:innocent: :wink: :+1:

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I saw that after login if I use the set-brightness buttons and change the state, the backlight will start to work. After searching around I may have found a solution.

I saw that I can edit the light level via the command line with:

echo 75 > /sys/class/backlight/nv_backlight/brightness

Where the number after echo is the % of the light level in my particular case.

After that I got an idea to force lightdm to actually touch the file and just set the light level to the one in that file right before the user login screen is shown as setting it via buttons actually enables it.

So I just added in /etc/lightdm/lightdm.conf this line:

greeter-setup-script = touch /sys/class/backlight/nv_backlight/brightnes

And now I actually don't have this issue anymore!

Hope it helps someone who has this issue as I haven't seen a workaround except upgrade kernels/drivers.

P.S. Sorry for any spaghetti text, it's quite late and I'm tired.


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