Can't adjust brightness on a HP Pavillion Dv3

I can not adjust the screen brightness on my HP Pavillion Dv3-2154ca, using Ubuntu 11.10. My Fn-f7/f8 keys don't work (they just show a changing screen brightness bar, with no effect), and adjusting 'screen brightness' does nothing as well.

I'm new to Ubuntu/Linux, so simple answers would be much appreciated!

3 Answers

I think that your problem is similar to this one. Because you use Ubuntu 11.10, you don't have to change the kernel, because kernel 3.0 is already patched with the fix. But, according to what is reported in the specified PPA, you may still need a fix to the boot options:

sudo -H gedit /etc/default/grub

Change the line GRUB_CMDLINE_LINUX="" into

GRUB_CMDLINE_LINUX="acpi_backlight=vendor"

Run:

sudo update-grub

Restart Ubuntu

Please try this:

1. sudo -H gedit /etc/rc.local

2. Before the exit 0 statement, write

   echo your_brightness > /sys/class/backlight/acpi_video0/brightness

   where your_brightness means a number (1 - 10).

3. Example echo 5 > /sys/class/backlight/acpi_video0/brightness
4. Reboot

Don't forget: You will need to run sudo update-grub if you want the changes in /etc/default/grub to be there when you reboot!