Comment 0 for bug 1243897

After upgrade from 13.04 to 13.10, setting the screen brightness has no effect (either via the hotkeys, "Brightness & Lock" settings, or via /sys/devices/pnp0/00:07/backlight/gmux_backlight/brightness ).

I'm using nvidia driver 319.32-0ubuntu7.
I've tried Option "RegistryDwords" "EnableBrightnessControl=1" in xorg.conf as well as the kernel argument acpi_backlight=vendor .

I have the following in /sys:
$ find /sys -name brightness
/sys/devices/pnp0/00:07/backlight/gmux_backlight/brightness
/sys/devices/pci0000:00/0000:00:1c.0/0000:03:00.1/leds/mmc0::/brightness
/sys/devices/platform/applesmc.768/leds/smc::kbd_backlight/brightness

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: linux-image-3.11.0-12-generic 3.11.0-12.19
ProcVersionSignature: Ubuntu 3.11.0-12.19-generic 3.11.3
Uname: Linux 3.11.0-12-generic x86_64
NonfreeKernelModules: wl nvidia
ApportVersion: 2.12.5-0ubuntu2
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: levi 2136 F.... pulseaudio
 /dev/snd/controlC0: levi 2136 F.... pulseaudio
 /dev/snd/pcmC0D0p: levi 2136 F...m pulseaudio
Date: Wed Oct 23 21:25:29 2013
HibernationDevice: RESUME=UUID=0c3f021e-1d6f-4ed4-a9e4-00ff145e91ef
InstallationDate: Installed on 2012-08-24 (425 days ago)
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Alpha amd64+mac (20120724.2)
MachineType: Apple Inc. MacBookPro10,1
MarkForUpload: True
ProcFB: 0 EFI VGA
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.11.0-12-generic root=UUID=2888919c-46a6-41be-874a-f3af7333ec15 ro quiet splash nomodeset nomodeset acpi_backlight=vendor vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.11.0-12-generic N/A
 linux-backports-modules-3.11.0-12-generic N/A
 linux-firmware 1.116
SourcePackage: linux
UpgradeStatus: Upgraded to saucy on 2013-10-17 (5 days ago)
dmi.bios.date: 08/08/2012
dmi.bios.vendor: Apple Inc.
dmi.bios.version: MBP101.88Z.00EE.B02.1208081132
dmi.board.asset.tag: Base Board Asset Tag#
dmi.board.name: Mac-C3EC7CD22292981F
dmi.board.vendor: Apple Inc.
dmi.board.version: MacBookPro10,1
dmi.chassis.type: 10
dmi.chassis.vendor: Apple Inc.
dmi.chassis.version: Mac-C3EC7CD22292981F
dmi.modalias: dmi:bvnAppleInc.:bvrMBP101.88Z.00EE.B02.1208081132:bd08/08/2012:svnAppleInc.:pnMacBookPro10,1:pvr1.0:rvnAppleInc.:rnMac-C3EC7CD22292981F:rvrMacBookPro10,1:cvnAppleInc.:ct10:cvrMac-C3EC7CD22292981F:
dmi.product.name: MacBookPro10,1
dmi.product.version: 1.0
dmi.sys.vendor: Apple Inc.