Oh yeah! #24 is really dirty one! But it gave me a clue, how this bug should be fixed: Patching StepUp/StepDown handlers is very bad practice, because these methods may be called by some other applications. We need to prevent calls to these methods depending on some parameter.
The problem itself: bios changes brightness on keypress and reports acpi keypress event, instead of just reporting event (this might be fixable in DSDT), then some process handles this event and issues dbus calls to org.gnome.SettingsDaemon.Power.Screen.StepUp/StepDown methods. Then g-p-m changes brightness too; g-p-m has no ways to determine, whether it should change brightness when handling StepUp/StepDown dbus calls, or not. Neither 'some process' do. The solution, how I see it: find code, which handles acpi keypresses (that's not g-p-m, g-s-d may be?) and add user-changeable option there to disable acpi brightness keypresses handle (e.g. gconf parameter). -- 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
