Intel Ultrabook tweaks on Ubuntu 12.04

After upgrading my Toshiba Z830 Ultrabook to 12.04 (Precise Pangolin) I noticed that the ability to control the screen back-light was not working using the Toshiba Fn F6/F7 keys.

Thanks to http://www.linlap.com/wiki/acer+aspire+s3 the solution was found quite quickly.

sudo vim /etc/default/grub

This will open the grub configuration file. (Grub is the initial boot selection software)
To be able to dim the screen brightness, You’ve got to modify the line:

GRUB_CMDLINE_LINUX=""

to these two lines:

pcie_aspm=force
GRUB_CMDLINE_LINUX="quiet splash pcie_aspm=force i915.i915_enable_rc6=1 i915.lvds_downclock=1 acpi_osi=Linux acpi_backlight=vendor elevator=noop"

Another neat tip: intel-gpu-tools can be used to control brightness from the commandline.

# will set brightness at 50%
intel_backlight 50

EDIT [2012-08-24]: to avoid issues on resume you need to add a script to the

sudo vim /etc/pm/sleep.d/20_wakeup

Add the following:

#!/bin/bash
case "$1" in
suspend|hibernate)
#do nothing
;;
resume|thaw)
echo 7 > /sys/class/backlight/toshiba/brightness
;;
*)
exit 1
;;
esac
exit 0

Mark the file as executable

sudo chmod +x /etc/pm/sleep.d/20_wakeup

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