Comment 0 for bug 1165590

Hi,

gsd-backlight-helper seems to make a wrong decision on which backlight to modify/the correct node is missing. The hotkeys for changing the screen brightness don't work on Asus UX32VD. The brightness is stuck between two values ​​ with the hotkeys (about 95% and 90%)

gsd-backlight-helper sets /sys/devices/virtual/backlight/apple_backlight/brightness which doesn't change anything :

# strace -e write,open /usr/lib/gnome-settings-daemon/gsd-backlight-helper --set-brightness 10 2>&1|tail -n 2
open("/sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0/backlight/acpi_video0/brightness", O_WRONLY) = 3
write(3, "10", 2) = 2

manually setting the brightness like this doesn't work :

# echo 5 > /sys/devices/pci0000\:00/0000\:00\:01.0/0000\:01\:00.0/backlight/acpi_video0/brightness

setting the brightness using intel_backlight works well :

# strace -e write,open /usr/bin/intel_backlight 100 2>&1|tail -n 4
open("/sys/bus/pci/devices/0000:00:02.0/resource0", O_RDWR|O_CLOEXEC) = 4
write(1, "current backlight value: 100%\nse"..., 52current backlight value: 100%
set backlight to 100%
) = 52

manually setting the brightness like this works :

# echo 50 > /sys/bus/pci/devices/0000\:00\:02.0/backlight/acpi_video1/brightness

ProblemType: Bug
DistroRelease: Ubuntu 13.04
Package: gnome-settings-daemon 3.6.4-0ubuntu8
ProcVersionSignature: Ubuntu 3.8.0-16.26-generic 3.8.5
Uname: Linux 3.8.0-16-generic x86_64
ApportVersion: 2.9.2-0ubuntu5
Architecture: amd64
Date: Sun Apr 7 07:41:38 2013
InstallationDate: Installed on 2012-09-17 (201 days ago)
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Alpha amd64+mac (20120917)
MarkForUpload: True
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: gnome-settings-daemon
UpgradeStatus: Upgraded to raring on 2013-04-06 (0 days ago)