13.04 - Backlight Display Brightness Doesn't Change (Fn + Left/Right Keys)

[4Sci]

Hi, new forum poster here. I can't adjust the backlight brightness using the function + left/right keys on my Acer laptop. In previous versions of Ubuntu (12.04, 12.10), this was fixed by editing /etc/default/grub and adding

"acpi_backlight=vendor"
to
"GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
and then
"sudo update-grub"

This no longer seems to work in 13.04. What should I do? Thanks

[slickymaster]

Instead of

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

modify it to

 GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"

or if it still doesn't work, modify it to

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux acpi_backlight=vendor"

Save and close /etc/default/grub​, update grub:

sudo update-grub

and reboot your computer.

Edit: And be very welcome to the forums.

[4Sci]

Thank you! I had to add "acpi_osi=Linux" to that grub line to get it working.

[slickymaster]

Thank you! I had to add "acpi_osi=Linux" to that grub line to get it working.

There is no need to thank, we're all here to help each other. Please mark this thread as solved so other people searching the forums know that this thread provides a working solution for their problem. If you don't know how, follow the link in my signature on how to do it.

[JustANewb]

Instead of

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

modify it to

 GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"

or if it still doesn't work, modify it to

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux acpi_backlight=vendor"

Save and close /etc/default/grub​, update grub:

sudo update-grub

and reboot your computer.

Edit: And be very welcome to the forums.

Just came here to post thanks for this. Helped me to get my brightness keys working again on Ubuntu 13.04 on my Acer Aspire V5-571P-6831.

[davihn67]

it doesn't work for me, i have the same computer, please help