I recently upgraded from xubuntu 14.04 to 14.10 and then to 15.04 on Lenovo z580. I used to control brightness on 14.04 using xbacklight from command line. Now its not working. 15.04 also has a brightness control option in power management plugin. This one also not working. How to troubleshoot this problem?
1 Answer
I had the same problem in Ubuntu 15.04. This is how I solved it.
First use ls /sys/class/backlight/
to see which video card is installed. In my case the above command showed intel_backlight
. After this I did:
sudo touch /usr/share/X11/xorg.conf.d/20-intel.conf # create 20-intel.conf file`
sudo gedit /usr/share/X11/xorg.conf.d/20-intel.conf #open the file
and add the following lines to this file
Section "Device"
Identifier "card0"
Driver "intel"
Option "Backlight" "intel_backlight"
BusID "PCI:0:2:0"
EndSection
save and exit. Log out and log-in back.
Try the following if the above did not work:
sudo nano /etc/default/grub
Make the line that say GRUB_CMDLINE_LINUX=""
to look like the following:
GRUB_CMDLINE_LINUX="acpi_backlight=vendor"
Update grub by: sudo update-grub
and reboot.
As a final option try this: xrandr --output LVDS1 --brightness 0.8
. Play with numbers other than 0.8 and see what happens.
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Can you please tell what does
cat /etc/default/grub | grep GRUB_CMDLINE_LINUX=
say too.– RonApr 29, 2015 at 18:03 -