Can't change screen brightness on Toshiba P855-30D

[Julien Cornuwel]

The brightness is locked to the brightest setting (eye-melting-bright).
I upgraded to the latest BIOS to this date : 6.70
Below are my different attempts at setting the brightness using the command line (GUI don't work either).

GRUB_CMDLINE_LINUX=""
/sys/class/backlight/ is populated
/sys/class/backlight/acpi_video0/max_brightness:100
changing /sys/class/backlight/acpi_video0/brightness has no effect

GRUB_CMDLINE_LINUX="acpi_osi=Linux acpi_backlight=vendor"
/sys/class/backlight/ is empty

GRUB_CMDLINE_LINUX="acpi_osi="
/sys/class/backlight/ is populated
/sys/class/backlight/acpi_video0/max_brightness:7
changing /sys/class/backlight/acpi_video0/brightness has no effect

GRUB_CMDLINE_LINUX="acpi_osi=\"!Windows 2012\""
/sys/class/backlight/ is populated
/sys/class/backlight/acpi_video0/max_brightness:7
changing /sys/class/backlight/acpi_video0/brightness has no effect

ProblemType: Bug
DistroRelease: Ubuntu 13.04
Package: linux-image-3.8.0-23-generic 3.8.0-23.34
ProcVersionSignature: Ubuntu 3.8.0-23.34-generic 3.8.11
Uname: Linux 3.8.0-23-generic x86_64
ApportVersion: 2.9.2-0ubuntu8.1
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: julien 2020 F.... pulseaudio
 /dev/snd/controlC0: julien 2020 F.... pulseaudio
Date: Mon Jul 8 19:12:15 2013
HibernationDevice: RESUME=UUID=26161152-fbf6-4974-b0cd-1986c7a4c449
InstallationDate: Installed on 2013-05-18 (51 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
MachineType: TOSHIBA SATELLITE P855
MarkForUpload: True
ProcFB: 0 nouveaufb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.8.0-23-generic root=UUID=dccd4184-97e2-47cd-a183-884c6e410dec ro "acpi_osi=!Windows 2012" quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.8.0-23-generic N/A
 linux-backports-modules-3.8.0-23-generic N/A
 linux-firmware 1.106
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 02/20/2013
dmi.bios.vendor: TOSHIBA
dmi.bios.version: 6.70
dmi.board.asset.tag: *
dmi.board.name: QFKAA
dmi.board.vendor: TOSHIBA
dmi.board.version: 1.00
dmi.chassis.asset.tag: *
dmi.chassis.type: 10
dmi.chassis.vendor: TOSHIBA
dmi.chassis.version: *
dmi.modalias: dmi:bvnTOSHIBA:bvr6.70:bd02/20/2013:svnTOSHIBA:pnSATELLITEP855:pvrPSPKBE-04C00CFR:rvnTOSHIBA:rnQFKAA:rvr1.00:cvnTOSHIBA:ct10:cvr*:
dmi.product.name: SATELLITE P855
dmi.product.version: PSPKBE-04C00CFR
dmi.sys.vendor: TOSHIBA

[Brad Figg (brad-figg)]

This change was made by a bot.

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v3.10 kernel[0].

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

If you are unable to test the mainline kernel, for example it will not boot, please add the tag: 'kernel-unable-to-test-upstream'.
Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.10-saucy/

[Julien Cornuwel (cornuwel)]

Done. I tried all 4 ACPI config values, same results.

Funny enough, trying this broke my user session.
I had my desktop background, I could right-click it, but no launcher and no 'super' shortcuts...
I renamed my homedir and created a new directory and it started like normal.
Now, I have to find what's broken in it :-/

Regards

[penalvch (penalvch)]

Julien Cornuwel, thank you for reporting this and helping make Ubuntu better. Could you please provide the information following https://wiki.ubuntu.com/Kernel/Debugging/Backlight ?

[Julien Cornuwel (cornuwel)]

Hi, I haven't followed the given link yet, but I found a solution : use nvidia's proprietary drivers.
As soon as the driver is loaded, the settings scrollbar is working. Not the hotkeys though...
I'll have a look into that.

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]