I cannot change the brightness of my HP EliteBook 8760w. When I press the brightness keys, ubuntu shoes the meter going down and up, but the screen brightness does not change.
I am using nvidia drivers 367.57 for the Quadro 3000M.
user@laptop:~$ ls /sys/class/backlight/
acpi_video0
user@laptop:~$ cat /sys/class/backlight/*/brightness
20
user@laptop:~$ cat /sys/class/backlight/*/max_brightness
20
user@laptop:~$ sudo su -c "echo 5 > /sys/class/backlight/*/brightness"
user@laptop:~$ cat /sys/class/backlight/*/brightness
5
Is there anything else I could try to change the brightness?
I tried changing /etc/default/grub
to add additional parameters to acpi_backlight
. The following happens:
(not defining) only acpi_video0 exists and brightness does not work
video only acpi_video0 exists and brightness does not work
vendor no folder in /sys/class/backlight
native no folder in /sys/class/backlight
/etc/default/grub
, add the parameteracpi_backlight=vendor
to the variableGRUB_CMDLINE_LINUX_DEFAULT
save the file, runsudo update-grub
and restart. Here are the references wiki.archlinux.org/index.php/backlight and wiki.ubuntu.com/Kernel/Debugging/Backlight.acpi_backlight=vendor
it behaves exactly like without defining. when defining it asvendor
ornative
theacpi_video0
folder is missing completely. i am speaking of the built-in laptop monitor. I know the brightness worked years ago... on some ubuntu dist.vendor
gives you noacpi_video0
folder as well.