Brightness on Lenovo
Hello, I need some help about brightness on my laptop Lenovo 110 series. I've installed Trisquel 7 and updated it, but when I move the brightness bar nothing happens. It' doesn't go down but it's blocked at the maximum level of brighteness. I tried various methods, like changing the /etc/default/grub file but nothing works for me. I can't use the laptop for now because of the maximum brightness, someone can help me please?
Please be more precise about your hardware (what video card?, does the laptop have function keys to adjust the brightness?) and about what you have attempted so far (I guess you tried to add "acpi_backlight=vendor" to GRUB_CMDLINE_LINUX_DEFAULT and "acpi_osi=Linux" to GRUB_CMDLINE_LINUX but that is only a guess).
Assuming you use an Intel graphical chipset ('lspci', in a terminal, would tell), does the following command (where 60 is an example of brightness value) changes the brightness?
$ echo 60 | sudo tee /sys/class/backlight/intel_backlight/brightness
If you use an nVidia card, the file should be /sys/class/backlight/nv_backlight/brightness instead of /sys/class/backlight/intel_backlight/brightness
If it does work, your preferred value can be set at startup by writing something like that (change the value and maybe the file) before the exit command in /etc/rc.local:
echo 60 > /sys/class/backlight/intel_backlight/brightness
A more recent kernel may help too (including to get function keys properly working): https://jxself.org/linux-libre/
ADFENO also wrote a script to easily adjust the brightness when the function keys do not work: https://trisquel.info/forum/grub-bootloader-trick-doesnt-work#comment-112392
An older thread on a similar issue.
https://trisquel.info/en/forum/toutatis-brightness-control#comment-57107
I tried to write echo 60 | sudo tee /sys/class/backlight/intel_backlight/brightness but nothing changes, I also tryed to modify actual_brightness with sudo but it says "permission denied". I have an intel graphic HD 520, I tried also the others solutions on the forum but nothings work. Can someone help me? If my brightness doesn't go down I can't use the laptop...
News:
Now I restart my laptop and there is nothing in backlight folder...
Try this.
echo X >/sys/class/backlight/acpi_video0/brightness
Where 'x' is a number (try 10 or something).
You'll have to do it as root (not sudo prefix, but 'su' first).
I have Intel HD on my HP laptop, and this command works.
Again: please answer the question at the beginning of https://trisquel.info/forum/brightness-lenovo#comment-117401 if you want valuable help instead of random solutions that probably do not apply to your hardware. Have you tried to install a newer kernel from https://jxself.org/linux-libre/ (the easiest way)?
I've installed the newest linux libre kernel but nothing changed....
https://itsfoss.com/fix-brightness-ubuntu-1310/
On an ubuntu notebook I got brightness to work using the instructions.