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Topic: [SOLVED] Brightness is set to the max value but display is still black (Read 489 times) previous topic - next topic
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[SOLVED] Brightness is set to the max value but display is still black

Hi, I recently installed a program called brillo to adjust my laptop screen brightness.

After a couple of minutes installing and giving my user permission to use the edit the brightness file, I rebooted my laptop, but now the screen is pitch black.

Luckily I have an external monitor that works well and that I can use.

[h]What I know[/h]

1. It is not an LCD issue, I can still exit X and it prompts me into the tty on my laptop.
2. Setting my brightness with the following command does nothing, since it is already at the max brightness by default.
Code: [Select]
echo <value> > /sys/class/backlight/amdgpu_bl0/brightness

Here is what the current brightness is set at:

Code: [Select]
$ cat /sys/class/backlight/amdgpu_bl0/brightness
225

And here is max brightness:

Code: [Select]
$ cat /sys/class/backlight/amdgpu_bl0/max_brightness
255

3. The display is connected and active

My laptop display is still connected and active. I can see it using xrandr and I can even record it with OBS.

I think the issue is that it is stuck with a brightness value of zero, even though it is specifically set to the max value.

4. Removing brillo does not help, rebooting does not help.

[h]System Specifications[/h]

Here is a Neoftech output:

Code: [Select]
iq@z13
------
OS: Artix Linux x86_64
Host: 21D2CTO1WW ThinkPad Z13 Gen 1
Kernel: 6.3.9-artix1-1
Shell: bash 5.1.16
Resolution: 1920x1200, 3840x1600
WM: xmonad
CPU: AMD Ryzen 7 PRO 6860Z with Radeon Graphics (16) @ 2.700GHz
GPU: AMD ATI Radeon 680M
Memory: 2115MiB / 31358MiB

Re: Brightness is set to the max value but display is still black

Reply #1 –
The fact that removing the package and rebooting hasn't fixed it sugessts something has been left behind?

Maybe in /etc/tmpfiles.d or /etc/sysctl.d  ?

Other than that maybe ask the author https://gitlab.com/cameronnemo/brillo/-/issues ?

Re: Brightness is set to the max value but display is still black

Reply #2 –
Actually I've figured out that the brightness is not the issue here.

It's that seems to turn off when X is launched. I can still use brillo in the TTY to change the backlight, and I can see the changes.

However, once I start X, I can't notice those changes because the display is off.

Still no idea how to fix that issue.

Re: Brightness is set to the max value but display is still black

Reply #3 –
Hi,

I temporarily fixed the issue by changing my resolution.

The default resolution on my laptop is 1920x1200, but it seems like if I put anything but 2880x1800, the display turns completely black.

I am still looking for a fix for that particular resolution issue... 2880x1800 is unusable.

Re: Brightness is set to the max value but display is still black

Reply #4 –
Quote
2880x1800 is unusable
I'd like to interject here, just set Xft.dpi higher, or adjust the scaling setting in xrandr, will look very good. Of course for a bit more battery the low res makes sense still.

LE: Speaking of that, wait a second, that program maybe overwritten the display output modes. Does anything happen if you run DISPLAY=:0 xrandr -s 0? https://askubuntu.com/questions/261122/how-to-reset-monitor-settings-to-default-through-terminal

Re: Brightness is set to the max value but display is still black

Reply #6 –
Hi, I just switched to a different kernel and everything is working fine.

I am running zen now.

Thank you all!