Brightness in laptop

EdPeter · 2024-09-19 06:57

Hi!

I decided to make a new topic with this problem: changing display brightness level doesn't work, which means:
- using function keys on my laptop shows me increasing/decreasing bar with percentage, but it doesn't affect the display
- the same with using mouse scroll when I opened brightness settings (right down corner, next to clock, I don't know the English name - I use Linux in Polish)
- when I use function keys on laptop, and type command:

cat /sys/class/backlight/acpi_video0/brightness

I see that the value was changed, but no effects on screen.
- I tried xbacklight, but it doesn't work, I get "No outputs have backlight property", probably doesn't support my card

I have:
acpi_video0

Peter@q4ospc:~$ ls -l /sys/class/backlight/
razem 0
lrwxrwxrwx 1 root root 0 09-19 06:40 acpi_video0 -> ../../devices/pci0000:00/0000:00:01.0/0000:02:00.0/backlight/acpi_video0

02:00.0 VGA compatible controller: NVIDIA Corporation GT218M [GeForce 315M] (rev a2) (prog-if 00 [VGA controller])
Subsystem: Samsung Electronics Co Ltd GeForce 315M
Flags: bus master, fast devsel, latency 0, IRQ 29
Memory at dc000000 (32-bit, non-prefetchable) [size=16M]
Memory at e0000000 (64-bit, prefetchable) [size=256M]
Memory at de000000 (64-bit, prefetchable) [size=32M]
I/O ports at 2000 [size=128]
Expansion ROM at 000c0000 [virtual] [disabled] [size=128K]
Capabilities: <access denied>
Kernel driver in use: nouveau
Kernel modules: nouveau

I've found such command (the goal was set ~50% value of brightness), but I can't use it properly:

peter@q4ospc:/$ sudo setpci -s 00:02.0 F4.B=80
setpci: Warning: No devices selected for operation group 1.

hchiper · 2024-09-19 07:52

When I was using Q4OS 3, I had a similar problem and I found I could edit the file '/etc/default/grub' in the following way to solve the problem:

$ sudo cp /etc/default/grub /etc/default/grub.original # for safety, in case something goes wrong in the next steps
$ sudo micro /etc/default/grub # (I use micro as editor, change its name if you use another one)
find the line beginning with GRUB_CMDLINE_LINUX_DEFAULT
if it is not already there, add 'acpi_backlight=vendor' (without the single quotes) at the end of the line, within the existing double quotes
save the file
run $ update-grub (or maybe $ sudo update-grub)
reboot

I don't remember if I had to do it with Q4OS 4 too, and I can't say for Q4OS 5 because it is not installed on that laptop.

q4osteam · 2024-09-19 08:21

Did you check the settings in the systray panel area ? Screen brightness setting should work out of the box on Q4OS Plasma. If not, it's a bug or hardware incompatibility. It would be helpful, if you boot Debian live Plasma desktop media https://cdimage.debian.org/debian-cd/cu … 64-kde.iso , try change the brightness and send the result back.

We can also recommend checking the Debian solutions for your hardware, it will work for Q4OS as well.

EdPeter · 2024-10-07 18:54

If systray panel area is panel in the right down corner of desktop, then yes, I did use this - both on Q4OS and Debian - it doesn't work on my laptop. So, I will try to find solutions on Debian forums.

I remember that in the past I tried also Zorin, and ran up againts the same problem - too bright screen and no chances for changing it.

Q4OS Forum

#1 2024-09-19 06:57

Brightness in laptop

#2 2024-09-19 07:52

Re: Brightness in laptop

#3 2024-09-19 08:21

Re: Brightness in laptop

#4 2024-10-07 18:54

Re: Brightness in laptop

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