Happy Birthday Bug 527157! Gee, has it been two years already? It feels like just yesterday I was wondering why I couldn't get more than 5-7 brightness levels! Three Ubuntu releases later, and I've had to find two different solutions to the same problem. Maybe it's a g-p-m bug! Maybe it's a kernel bug! I've heard claims that the kernel is reporting xrandr brightness change failures even though the change actually succeeded. Who knows?!
For those of you who are tired of patching Gnome-Power-Manager, or trying unsuccesfully to patch the new version in the Gnome 3 branches, I may have found a solution less likely to get clobbered by system updates. The fix worked for this bug on my next laptop, an Alienware M11x r2. I've since moved on to OS X on a Macbook Air, but my hope is that it will help other poor souls just trying to get a comfortable brightness level. Add the following options to your kernel boot parameters: acpi_backlight=vendor I can't guarantee this will work on your laptop. It gave me 15 brightness levels on the Alienware (instead of the default 9 in windows or 4.5 in unmodified ubuntu). An unpleasant side effect was that the screen would go to sleep and not wake up, even though the system was still accessible via ssh. No amount of hand waving or xrandr prodding managed to fix this, or revive the comatose screen. I "solved" this by setting my display to never turn off unless I closed the screen. Despite my snark, I am appreciative of the work put in by people to fix this bug. I would like to thank everyone who helped out on this bug with your comments and testing. I would like to give special thanks to Darwin Bautista and Konstantin Lavrov for working so diligently on the original patch. Your work let me use my machine with the proper brightness levels right up until the 3.x tree of GPM. Without you guys (and especially Darwin's ppa), I would've never had proper screen brightness, and would've never known where to look when resolving this issue in the next version of GPM. >From the bottom of my heart, thank you all. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-power-manager in Ubuntu. https://bugs.launchpad.net/bugs/527157 Title: Brightness controls skips Levels. Status in “gnome-power-manager” package in Ubuntu: Triaged Status in “gnome-power-manager” package in Arch Linux: New Bug description: Binary package hint: gnome-power-manager Expected: Hitting brightness up key or brightness down key changes brightness by one level out of 15. Actual: Hitting brightness up key or brightness down key changes brightness by two or three levels out of 15. When I use the brightness control keys from a fresh install, the brightness jumps THREE increments. By creating /etc/modprobe.d/video.conf and setting options video brightness_switch_enabled = 0 I reduce this to consistently TWO brightness events, but this is still double the normal events. If I kill gnome-power-manager, it returns to single brightness events. when hitting brightness up/down with gnome-power-manager, udevmonitor shows UDEV - the event which udev sends out after rule processing KERNEL - the kernel uevent KERNEL[1267026969.897008] change /devices/virtual/backlight/acpi_video0 (backlight) UDEV [1267026969.898270] change /devices/virtual/backlight/acpi_video0 (backlight) KERNEL[1267026969.903078] change /devices/virtual/backlight/acpi_video0 (backlight) UDEV [1267026969.903842] change /devices/virtual/backlight/acpi_video0 (backlight) KERNEL[1267026971.355970] change /devices/virtual/backlight/acpi_video0 (backlight) UDEV [1267026971.357418] change /devices/virtual/backlight/acpi_video0 (backlight) with gnome-power-manager not running, it shows no events. Before: cat /proc/acpi/video/IGD0/LCD/brightness levels: 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 current: 25 Brightness up pressed: cat /proc/acpi/video/IGD0/LCD/brightness levels: 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 current: 40 With options video brightness_switch_enabled = 0: cat /proc/acpi/video/IGD0/LCD/brightness levels: 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 current: 25 Brightness up pressed: cat /proc/acpi/video/IGD0/LCD/brightness levels: 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 current: 35 With brightness_switch_enabled=0 and gnome-power-manager not running: cat /proc/acpi/video/IGD0/LCD/brightness levels: 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 current: 25 Brightness up pressed: cat /proc/acpi/video/IGD0/LCD/brightness levels: 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 current: 30 Description: Ubuntu lucid (development branch) Release: 10.04 xserver-xorg-video-intel: Installed: 2:2.9.1-1ubuntu1 Candidate: 2:2.9.1-1ubuntu1 Version table: *** 2:2.9.1-1ubuntu1 0 500 http://archive.linux.duke.edu lucid/main Packages 100 /var/lib/dpkg/status gnome-power-manager: Installed: 2.29.1-0ubuntu2 Candidate: 2.29.1-0ubuntu2 Version table: *** 2.29.1-0ubuntu2 0 500 http://archive.linux.duke.edu lucid/main Packages 100 /var/lib/dpkg/status To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-power-manager/+bug/527157/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
