Hi Christopher, I eventually managed to find the fix commit (this took me ages).
$ git bisect bad 751109aad5834375ca9ed0dcfcd85a00cbf872b5 is the first bad commit commit 751109aad5834375ca9ed0dcfcd85a00cbf872b5 Author: Rafael J. Wysocki <[email protected]> Date: Thu Jun 5 22:47:35 2014 +0200 ACPI / video: Change the default for video.use_native_backlight to 1 Now that we're hoping to have resolved all of the problems with video.use_native_backlight=1, make that the default at last. Link: http://marc.info/?l=linux-acpi&m=139716088401106&w=2 Signed-off-by: Rafael J. Wysocki <[email protected]> :040000 040000 d8f9ae057c052cd94f1adcfc0b298db2c728a315 933b38080034b141fc0c31f54f38f5b232f69c17 M drivers -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1335458 Title: [Toshiba Satellite Z930-164] Backlight control does not work, but there are entries in /sys/class/backlight Status in “linux” package in Ubuntu: Incomplete Bug description: Following bug reporting process: https://wiki.ubuntu.com/Kernel/Debugging/Backlight#Reporting_Backlight_Bugs Running Ubuntu 14.04 with Unity. Testing for a work around: * With kernel parameter acpi_backlight=vendor -> Brightness control is working with both applet and hotkeys. - # echo 8 > /sys/class/backlight/intel_backlight/brightness -> The command sets the screens brightness very low (almost turns it off). * With kernel parameter video.use_bios_initial_backlight=0 -> Brightness control is neither working with applet nor hotkeys. * With kernel parameter video.use_native_backlight=1 -> Brightness control is working with both applet and hotkeys. ProblemType: Bug DistroRelease: Ubuntu 14.04 Package: linux-image-3.13.0-30-generic 3.13.0-30.54 ProcVersionSignature: Ubuntu 3.13.0-30.54-generic 3.13.11.2 Uname: Linux 3.13.0-30-generic x86_64 ApportVersion: 2.14.1-0ubuntu3.2 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: florent 2107 F.... pulseaudio CurrentDesktop: Unity Date: Sat Jun 28 18:17:42 2014 EcryptfsInUse: Yes HibernationDevice: RESUME=/dev/mapper/toshnux--vg-swap_1 MachineType: TOSHIBA SATELLITE Z930 ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-30-generic root=/dev/mapper/hostname--vg-root ro splash quiet acpi_backlight=vendor vt.handoff=7 RelatedPackageVersions: linux-restricted-modules-3.13.0-30-generic N/A linux-backports-modules-3.13.0-30-generic N/A linux-firmware 1.127.4 SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 04/04/2013 dmi.bios.vendor: TOSHIBA dmi.bios.version: Version 6.70 dmi.board.asset.tag: 0000000000 dmi.board.name: SATELLITE Z930 dmi.board.vendor: TOSHIBA dmi.board.version: Version A0 dmi.chassis.asset.tag: 0000000000 dmi.chassis.type: 10 dmi.chassis.vendor: TOSHIBA dmi.chassis.version: Version 1.0 dmi.modalias: dmi:bvnTOSHIBA:bvrVersion6.70:bd04/04/2013:svnTOSHIBA:pnSATELLITEZ930:pvrPT23LE-01900EFR:rvnTOSHIBA:rnSATELLITEZ930:rvrVersionA0:cvnTOSHIBA:ct10:cvrVersion1.0: dmi.product.name: SATELLITE Z930 dmi.product.version: PT23LE-01900EFR dmi.sys.vendor: TOSHIBA To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1335458/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
