Toshiba R700 backlight control not always working

[Alan Pater]

When returning from sleep mode, I lose backlight control via Fn-F7.

Restarting the system restores control.

I am running Ubuntu 14.04 64 bit.
~$ uname -psrv
Linux 3.13.0-37-generic #64-Ubuntu SMP Mon Sep 22 21:28:38 UTC 2014 x86_64

I could also adjust the brightness from the terminal:

~$ cat /sys/class/backlight/intel_backlight/brightness
1030

~$ grep . /sys/class/backlight/intel_backlight/*
/sys/class/backlight/intel_backlight/actual_brightness:1030
/sys/class/backlight/intel_backlight/bl_power:0
/sys/class/backlight/intel_backlight/brightness:1030
/sys/class/backlight/intel_backlight/max_brightness:4539

So, to temporarily increase the screen brightness:

~$ echo 3030 | sudo tee /sys/class/backlight/intel_backlight/brightness
3030

But that does not give back control via Fn-F7, it just gives an independent way of adjusting the backlight.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-3.13.0-37-generic 3.13.0-37.64
ProcVersionSignature: Ubuntu 3.13.0-37.64-generic 3.13.11.7
Uname: Linux 3.13.0-37-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.5
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: asp 2789 F.... pulseaudio
CRDA:
 country PE:
  (2402 - 2482 @ 40), (N/A, 20)
  (5735 - 5835 @ 40), (N/A, 30)
CurrentDesktop: Unity
Date: Fri Oct 24 13:56:26 2014
HibernationDevice: RESUME=UUID=7d358de7-c06d-487c-959d-6d6f94292a9c
InstallationDate: Installed on 2014-03-08 (229 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Alpha amd64 (20140304)
MachineType: TOSHIBA PORTEGE R700
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-37-generic root=UUID=82477238-1cd0-4280-b615-9e54c4178914 ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.13.0-37-generic N/A
 linux-backports-modules-3.13.0-37-generic N/A
 linux-firmware 1.127.7
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 12/22/2011
dmi.bios.vendor: TOSHIBA
dmi.bios.version: Version 2.20
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:bvrVersion2.20:bd12/22/2011:svnTOSHIBA:pnPORTEGER700:pvrPT311Q-02S02U:rvnTOSHIBA:rnPortablePC:rvrVersionA0:cvnTOSHIBA:ct10:cvrVersion1.0:
dmi.product.name: PORTEGE R700
dmi.product.version: PT311Q-02S02U
dmi.sys.vendor: TOSHIBA

[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 v3.18 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/v3.18-rc1-utopic/

[Brad Figg (brad-figg)]

This change was made by a bot.

[Alan Pater (alan-pater)]

Upstream kernel linux-image-3.18.0-031800rc1-generic locked up the system when playing with the backlight control.

[Alan Pater (alan-pater)]

Tried the 3.17 upstream kernel. It did not fix the issue.

:~$ uname -psrv
Linux 3.17.1-031701-generic #201410150735 SMP Wed Oct 15 11:36:31 UTC 2014 x86_64

[penalvch (penalvch)]

Alan Pater, could you please provide the full computer model (ex. Toshiba Portege R700-S1331), Serial Number, and country of origin of the computer as noted on the sticker of the computer itself (not from the Bug Description)?

[Alan Pater (alan-pater)]

I'm afraid that the stickers are mostly worn off. The Portege R700 sticker is intact, but I don't see a legible model or serial number.
There is a P/N that starts with PT311... Is that the model number?

I highly suspect that it was originally sold in the USA, though I bought it second hand elsewhere.

[penalvch (penalvch)]

Alan Pater, would there be anything under the battery that would have this information?

[Alan Pater (alan-pater)]

No, nothing under the battery. Did Toshiba make a significant number of different versions of the R700?

[penalvch (penalvch)]

Alan Pater, let us put the full computer model aside for now. Hence, the issue you are reporting is an upstream one. Could you please report this problem to the linux-acpi mailing list (not bugzilla) by following the instructions _verbatim_ at https://wiki.ubuntu.com/Bugs/Upstream/kernel ?

Please provide a direct URL to your e-mail to the mailing list once you have made it so that it may be tracked.

Thank you for your understanding.

[Alan Pater (alan-pater)]

Done. Reported to the linux-acpi mailing list. Can be followed here: http://marc.info/?t=141442299500005

[Alan Pater (alan-pater)]

As a workaround, creating an xorg.conf file and specifying "intel_backlight" seems to work, but I would love for this to work out of the box. Does something need to be changed in the kernel to recognize that this model of Toshiba uses the Intel Backlight?