Unable to change brightness in Lenovo B570 laptop
 

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.

Details:

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?

I run Ubuntu 11.04 64 bits with Unity on a Lenovo W520. So take my advice with caution
This should recreate your /etc/X11/xorg.conf:
On my laptop (remember, not running KDE, my solution to same problem as you was:
Add option "RegistryDwords" "EnableBrightnessControl=1" to the device section in /etc/X11/xorg.conf
reboot laptop
then run gnome-power-preferences
"on ac power" has a setting for back-light display (display brightness)

Nope, still no such file. This is probably because I don't have NVIDIA video card.

SOLVED

See the solution here: Unable to change brightness in a Lenovo laptop - Ask Ubuntu - Stack Exchange

what to do on gentoo?
 

hi,
nice to hear that theres a patch (ive been looking for it for 2 months now),
but how can i apply kamal's kernel patch to my gentoo kernel sources?
ive never patched a kernel before and i cant find the actual patch file, only the ubuntu package.
can sb help me?

greets, Foyaxe