Ubuntu
linux package

  1. Bug #765438
  2. Comment #65

Comment 65 for bug 765438

Revision history for this message
cgonzalez (cmgonzalez) wrote : Re: On startup, the backlight is off on laptop

Has been 2 years, but now i found a solution....for my emachines e725

here is kernel 3.5 rc 4 with all the i915 patches (i think):

http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.5-rc4-quantal/

install all the needed packages acording to your architectures i386 or amd64, for example for amd64:
dkpg -i
 linux-headers-3.5.0-030500rc4-generic_3.5.0-030500rc4.201206241635_amd64.deb
 linux-headers-3.5.0-030500rc4_3.5.0-030500rc4.201206241635_all.deb
 linux-image-3.5.0-030500rc4-generic_3.5.0-030500rc4.201206241635_amd64.deb
 linux-image-extra-3.5.0-030500rc4-generic_3.5.0-030500rc4.201206241635_amd64.deb

then you have to add to kernel boot parameters:

acpi_backlight=vendor
i915.invert_brightness=1

you can make them permant by editing /etc/default/grub , editing this line:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor i915.invert_brightness=1"

then run:

update-grub2

now you have your brightness working as on kernel 2.6-idontremember...

this patches has been liying around for a couple of months is a shame that no one from the canonical team, test them and create a ppa...