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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!

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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:

  1. sudo gedit /etc/default/grub
  2. Change the line GRUB_CMDLINE_LINUX="" into GRUB_CMDLINE_LINUX="acpi_backlight=vendor"
  3. run: sudo update-grub
  4. Restart Ubuntu
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Please try this:

  1. sudo gedit /etc/rc.local
  2. Before the exit 0 statement, write

    echo your_brightness > /sys/class/backlight/acpi_video0/brightness
  3. your_brightness means number (1 - 10).

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

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I think this was supposed to be a comment on the previous answer? :) – Caesium Jan 23 '12 at 16:56

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