Package: gnome-power-manager Version: 3.0.2-3 Severity: normal On a Sony Vaio VPCYA1V9E laptop, if I press Fn+F5 or Fn+F6, then gnome-power-manager attempts to change the brightness of the display backlight, and shows a window as if it had worked. However, the brightness does not change. Likewise, if I change the brightness via System Settings -> Screen, then the slider does move, but it has no effect.
Linux 3.1.0 detects two backlight devices: % ls -l /sys/class/backlight total 0 lrwxrwxrwx 1 root root 0 Dec 11 20:10 acpi_video0 -> ../../devices/pci0000:00/0000:00:02.0/backlight/acpi_video0 lrwxrwxrwx 1 root root 0 Dec 11 20:21 intel_backlight -> ../../devices/pci0000:00/0000:00:02.0/drm/card0/card0-LVDS-1/intel_backlight % cat /sys/class/backlight/acpi_video0/max_brightness 8 % cat /sys/class/backlight/acpi_video0/type firmware % cat /sys/class/backlight/intel_backlight/max_brightness 4882 % cat /sys/class/backlight/intel_backlight/type raw Of these, only intel_backlight actually affects the screen of the laptop; acpi_video0/brightness can be changed (by root) but does not seem to affect anything. (I haven't tried with an external display.) However, /usr/sbin/gnome-power-backlight-helper always chooses acpi_video0 and ignores intel_backlight. It has a built-in list of backlight devices that it tries to open; acpi_video0 is on this list but intel_backlight is not. Because it succeeds in opening acpi_video0, it does not read the /sys/class/backlight directory to see what other devices exist. GNOME 3.0 source code for selecting the backlight device: http://git.gnome.org/browse/gnome-power-manager/tree/src/gpm-backlight-helper.c?h=gnome-3-0#n52 In GNOME 3.2, the code has been moved to gnome-settings-daemon, but still does not recognize intel_backlight: http://git.gnome.org/browse/gnome-settings-daemon/tree/plugins/power/gsd-backlight-helper.c?h=gnome-3-2#n49 It would be best if backlight control worked correctly with the default settings. It seems the easiest way to achieve that is to add "intel_backlight" to the list in {gpm,gsd}-backlight-helper.c, somewhere above "acpi_video0" so that it takes precedence. Alternatively, Linux could perhaps be made to entirely omit the nonfunctional acpi_video0 backlight device and thereby cause gnome-power-backlight-helper to read the directory and find intel_backlight. The acpi_backlight=vendor kernel option seems like a step in the right direction, as it does make the /sys/class/backlight/acpi_video0 directory disappear. However, it also makes /sys/class/backlight/sony appear instead, and "sony" is on the list in gnome-power-backlight-helper, which therefore still does not read the directory. Unfortunately, backlight control via the sony directory does not work either; both brightness and actual_brightness are constantly -1 there. If I use acpi_backlight=vendor and unload the sony-laptop module, then the sony directory disappears too, gnome-power-backlight-helper opens intel_backlight, and I can finally change the brightness via the screen settings dialog box! That solution is still not satisfactory though, because Linux does not recognize the Fn+F5 and Fn+F6 key combinations without the sony-laptop module. The package-specific info below is incomplete because the bug-reporting script tried to use HAL and I don't have that installed. However, dmidecode shows: # dmidecode 2.11 SMBIOS 2.6 present. 17 structures occupying 853 bytes. Table at 0x000EA490. Handle 0x0000, DMI type 0, 24 bytes BIOS Information Vendor: INSYDE Version: R0070Z6 Release Date: 11/02/2010 ROM Size: 2048 kB Characteristics: PCI is supported PNP is supported BIOS is upgradeable BIOS shadowing is allowed Boot from CD is supported Selectable boot is supported EDD is supported 8042 keyboard services are supported (int 9h) CGA/mono video services are supported (int 10h) ACPI is supported USB legacy is supported Smart battery is supported BIOS boot specification is supported Function key-initiated network boot is supported Targeted content distribution is supported BIOS Revision: 0.70 Firmware Revision: 0.70 Handle 0x0001, DMI type 1, 27 bytes System Information Manufacturer: Sony Corporation Product Name: VPCYA1V9E Version: C9006WUT Serial Number: (removed from bug report) UUID: (removed from bug report) Wake-up Type: Power Switch SKU Number: N/A Family: VAIO Handle 0x0002, DMI type 2, 16 bytes Base Board Information Manufacturer: Sony Corporation Product Name: VAIO Version: N/A Serial Number: C9006WUT Asset Tag: N/A Features: Board is a hosting board Location In Chassis: Base Board Chassis Location Chassis Handle: 0x0003 Type: Motherboard Contained Object Handles: 0 (handles 0x0003 to 0x0010 removed from bug report) -- Package-specific info: Distro version: wheezy/sid Kernel version: 3.1.0-1-amd64 g-p-m version: 3.0.2 HAL version: System manufacturer: missing System version: missing System product: missing AC adapter present: no Battery present: no Laptop panel present: no CPU scaling present: no Battery Information: UPower data: Device: /org/freedesktop/UPower/devices/line_power_ADP1 native-path: /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:0c/PNP0C09:00/ACPI0003:00/power_supply/ADP1 power supply: yes updated: Sun Dec 11 20:10:53 2011 (1106 seconds ago) has history: no has statistics: no line-power online: no Device: /org/freedesktop/UPower/devices/battery_BAT0 native-path: /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:0c/PNP0C09:00/PNP0C0A:00/power_supply/BAT0 vendor: Sony Corp. model: VGP-BPS21B serial: (removed from bug report) power supply: yes updated: Sun Dec 11 20:29:02 2011 (17 seconds ago) has history: yes has statistics: yes battery present: yes rechargeable: yes state: discharging energy: 16.03 Wh energy-empty: 0 Wh energy-full: 40.56 Wh energy-full-design: 41.04 Wh energy-rate: 13.621 W voltage: 10.768 V time to empty: 1.2 hours percentage: 39.5217% capacity: 98.8304% technology: lithium-ion History (charge): 1323628142 39.522 discharging 1323628112 39.793 discharging 1323628082 40.089 discharging 1323628052 40.360 discharging History (rate): 1323628142 13.621 discharging 1323628112 13.518 discharging 1323628082 13.499 discharging 1323628052 13.311 discharging Daemon: daemon-version: 0.9.14 can-suspend: yes can-hibernate yes on-battery: yes on-low-battery: no lid-is-closed: no lid-is-present: yes is-docked: no GNOME Power Manager Process Information: HAL Process Information: -- System Information: Debian Release: wheezy/sid APT prefers testing APT policy: (500, 'testing') Architecture: amd64 (x86_64) Kernel: Linux 3.1.0-1-amd64 (SMP w/4 CPU cores) Locale: LANG=fi_FI.utf8, LC_CTYPE=fi_FI.utf8 (charmap=UTF-8) Shell: /bin/sh linked to /bin/dash Versions of packages gnome-power-manager depends on: ii consolekit 0.4.5-1 ii dbus-x11 1.4.16-1 ii dconf-gsettings-backend [gsettings-backend] 0.7.5-3 ii gnome-screensaver 3.0.1-3 ii gnome-settings-daemon 3.0.3-3 ii libc6 2.13-21 ii libcairo2 1.10.2-6.1 ii libcanberra-gtk3-0 0.28-3 ii libcanberra0 0.28-3 ii libglib2.0-0 2.30.2-4 ii libgnome-keyring0 3.2.0-3 ii libgtk-3-0 3.0.12-2 ii libnotify4 0.7.4-1 ii libpango1.0-0 1.29.4-2 ii libupower-glib1 0.9.14-3 ii libx11-6 2:1.4.4-4 ii libxext6 2:1.3.0-3 ii libxrandr2 2:1.3.2-2 ii notification-daemon 0.7.3-1 ii upower 0.9.14-3 Versions of packages gnome-power-manager recommends: ii udisks 1.0.4-2 Versions of packages gnome-power-manager suggests: ii policykit-1 0.102-2 -- no debconf information
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