I have a Toshiba Satellite R830 laptop with Ubuntu 12.04.1 64 bit. The Fn + F6 and Fn + F7 buttons adjust brightness until I put my laptop on sleep.
On wakeup they don't work any longer. Is there a solution or a workaround to this issue?
I found a better solution than the one selected above.
gksudo gedit /etc/default/grub
.GRUB_CMDLINE_LINUX_DEFAULT=
and modify it as follows: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux acpi_backlight=vendor"
.sudo update-grub
.Problem solved.
More info here: https://wiki.ubuntu.com/Kernel/Debugging/Backlight
This solution no longer works on 13.10 and 14.04.
A solution that does is creating an xorg configuration file:
sudo touch /usr/share/X11/xorg.conf.d/20-intel.conf
to create the file.sudo gedit /usr/share/X11/xorg.conf.d/20-intel.conf
to edit its content.Section "Device" Identifier "card0" Driver "intel" Option "Backlight" "intel_backlight" BusID "PCI:0:2:0" EndSection
Log out and in again.
Source: Fix Brightness Control Not Working for Ubuntu 13.10 & 14.04
I had the same problem with a Toshiba Portege R935 in 12.04, and I discovered this (not so elegant) workaround:
as root (not with sudo
but actually changing user: su root
), change the value in
sys/class/backlight/intel_backlight/brightness
for instance:
echo 2937 > /sys/class/backlight/intel_backlight/brightness
Warning: these values are not between 0
and 7
(as the ones in the other directory), but between 284
and 4539
, or something like that.