I managed to solve the problem in a much cleaner way. I tried to create a custom xorg.conf file with the following content but my system didn't boot.
Section "Device" Identifier "Intel Graphics" Driver "intel" Option "Backlight" "intel_backlight" # use your backlight that works here EndSection Finally, I tried the following procedure: http://askubuntu.com/a/281685/27968 I got errors when starting lightdm BUT it created a xorg.conf.failsafe file. I opened it and modified it by adding the option line under "Device" as follows: Section "Device" Identifier "Configured Video Device" Driver "intel" Option "Backlight" "intel_backlight" EndSection # Section "Monitor" Identifier "Configured Monitor" EndSection # Section "Screen" Identifier "Default Screen" Monitor "Configured Monitor" Device "Configured Video Device" EndSection And bingo! Everything is working as it should. -- 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/1069144 Title: [Toshiba Satellite R830-1H3] brightness control works until sleep Status in The Linux Kernel: Incomplete Status in “linux” package in Ubuntu: Triaged Bug description: On my Toshiba Satellite R830, I have 12.10 AMD64. The Fn + F6, Fn + F7 buttons reduce/increase the brightness level of the screen. The issue is that they stop working after waking my computer from sleep. When this happens I cannot even control brightness by going to "System Settings/Brightness and Lock". I had Ubuntu 12.04 installed before and I had the same identical problem. Now I installed the upstream kernel 3.7rc5 and the situation is even worse, because on wakeup, the brightness is at 100% whereas on the standard kernel it remembers the brightness value. WORKAROUND: I modified /etc/default/grub changing the line: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" to: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux acpi_backlight=vendor" Then updated grub with: sudo update-grub and the problem is solved. WORKAROUND: As root (not with sudo but actually changing user: su root), change the value in sys/class/backlight/intel_backlight/brightness . For instance: echo 2937 > /sys/class/backlight/intel_backlight/brightness or better still: echo 300 | sudo tee /sys/class/backlight/intel_backlight/brightness > /dev/null These values are not between 0 and 7 (as the ones in the other directory), but between 284 and 4539, or something like that. Source is http://askubuntu.com/a/196863/27968 . WORKAROUND: In Raring: echo 400 | sudo tee /sys/class/backlight/intel_backlight/brightness http://www.toshiba.co.uk/innovation/download_bios.jsp?service=UK Sent an e-mail upstream to: http://marc.info/?l=linux- acpi&m=136975088406475&w=2 ProblemType: Bug DistroRelease: Ubuntu 12.04 Package: linux-image-3.2.0-32-generic 3.2.0-32.51 ProcVersionSignature: Ubuntu 3.2.0-32.51-generic 3.2.30 Uname: Linux 3.2.0-32-generic x86_64 AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24. ApportVersion: 2.0.1-0ubuntu14 Architecture: amd64 ArecordDevices: **** List of CAPTURE Hardware Devices **** card 0: PCH [HDA Intel PCH], device 0: ALC269VB Analog [ALC269VB Analog] Subdevices: 1/1 Subdevice #0: subdevice #0 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: chris 1801 F.... pulseaudio Card0.Amixer.info: Card hw:0 'PCH'/'HDA Intel PCH at 0xc4820000 irq 49' Mixer name : 'Intel CougarPoint HDMI' Components : 'HDA:10ec0269,1179062e,00100100 HDA:80862805,11790001,00100000' Controls : 25 Simple ctrls : 12 Date: Sat Oct 20 19:04:25 2012 HibernationDevice: RESUME=UUID=7d4873fc-c21f-4172-977f-2fb7c1667f24 InstallationMedia: Ubuntu 12.04.1 LTS "Precise Pangolin" - Release amd64 (20120823.1) MachineType: TOSHIBA SATELLITE R830 ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-32-generic root=UUID=4ad29e86-825e-4c7c-b220-5eab7199b9e2 ro quiet splash vt.handoff=7 RelatedPackageVersions: linux-restricted-modules-3.2.0-32-generic N/A linux-backports-modules-3.2.0-32-generic N/A linux-firmware 1.79.1 SourcePackage: linux StagingDrivers: mei UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 07/31/2012 dmi.bios.vendor: TOSHIBA dmi.bios.version: Version 3.90 dmi.board.asset.tag: 0000000000 dmi.board.name: Portable PC 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:bvrVersion3.90:bd07/31/2012:svnTOSHIBA:pnSATELLITER830:pvrPT32LE-01Y00DFR:rvnTOSHIBA:rnPortablePC:rvrVersionA0:cvnTOSHIBA:ct10:cvrVersion1.0: dmi.product.name: SATELLITE R830 dmi.product.version: PT32LE-01Y00DFR dmi.sys.vendor: TOSHIBA --- ApportVersion: 2.6.1-0ubuntu6 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: chris 2074 F.... pulseaudio /dev/snd/pcmC0D0c: chris 2074 F...m pulseaudio /dev/snd/pcmC0D0p: chris 2074 F...m pulseaudio DistroRelease: Ubuntu 12.10 HibernationDevice: RESUME=UUID=7d4873fc-c21f-4172-977f-2fb7c1667f24 InstallationDate: Installed on 2012-09-19 (54 days ago) InstallationMedia: Ubuntu 12.04.1 LTS "Precise Pangolin" - Release amd64 (20120823.1) MachineType: TOSHIBA SATELLITE R830 MarkForUpload: True Package: linux (not installed) ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.5.0-18-generic root=UUID=4ad29e86-825e-4c7c-b220-5eab7199b9e2 ro quiet splash vt.handoff=7 ProcVersionSignature: Ubuntu 3.5.0-18.29-generic 3.5.7 RelatedPackageVersions: linux-restricted-modules-3.5.0-18-generic N/A linux-backports-modules-3.5.0-18-generic N/A linux-firmware 1.95 Tags: quantal running-unity Uname: Linux 3.5.0-18-generic x86_64 UpgradeStatus: Upgraded to quantal on 2012-10-23 (20 days ago) UserGroups: adm cdrom dialout dip lpadmin plugdev sambashare sudo dmi.bios.date: 07/31/2012 dmi.bios.vendor: TOSHIBA dmi.bios.version: Version 3.90 dmi.board.asset.tag: 0000000000 dmi.board.name: Portable PC 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:bvrVersion3.90:bd07/31/2012:svnTOSHIBA:pnSATELLITER830:pvrPT32LE-01Y00DFR:rvnTOSHIBA:rnPortablePC:rvrVersionA0:cvnTOSHIBA:ct10:cvrVersion1.0: dmi.product.name: SATELLITE R830 dmi.product.version: PT32LE-01Y00DFR dmi.sys.vendor: TOSHIBA To manage notifications about this bug go to: https://bugs.launchpad.net/linux/+bug/1069144/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp