Brightness adjustment keys [Fn] + [⇑]/[⇓] have no effect (although they are recognized by the environment), and I can't change the brightness using GUI tools as well. This seems like a problem in Linux itself, not the desktop environment.
I can change the brightness in Windows OS, so it's not some kind of hardware fault.
Lenovo B570 (Model Name: 20093)
Integrated Intel HD graphics card
Kubuntu 11.04 (Linux 2.6.38-10-generic, KDE 4.7.0), everything up to date
No proprietary graphics drivers (only Wi-Fi one)
What I've tried:
- Edit /etc/default/grub↦GRUB_CMDLINE_LINUX_DEFAULT: acpi_osi=Linux, acpi_backlight=vendor, nomodeset. And yes, I did update-grub
- Edit /etc/X11/xorg.conf (no such file, even after sudo dpkg-reconfigure xserver-xorg)
- Edit /proc/acpi/video/VGA/LCD/brightness (no such file)
- sudo setpci -s 00:02.0 F4.B=## (no effect)
- xbacklight -set ## ("No outputs have backlight property")
How can I fix this issue?
This has been fixed in Ubuntu 11.10!
Solution for older distributions