8086:0046 Screen brightness can not be adjusted in Raring with Intel Ironlake graphics

[Ethan Shalev]

I had no problem with 12.04 or 12.10, but upon upgrading to 13.04, once again, I cannot adjust the screen brightness. It is stuck at 100%.

WORKAROUND: GRUB_CMDLINE_LINUX="acpi_osi=Linux" now allows me to adjust the brightness, although at boot, it's set to 0.

ProblemType: Bug
DistroRelease: Ubuntu 13.04
Package: linux-image-3.8.0-19-generic 3.8.0-19.30
ProcVersionSignature: Ubuntu 3.8.0-19.30-generic 3.8.8
Uname: Linux 3.8.0-19-generic x86_64
ApportVersion: 2.9.2-0ubuntu8
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: ethan 2358 F.... pulseaudio
CheckboxSubmission: 4463f48e66443bc710cec4d3024fcac7
CheckboxSystem: 090f50ffa15f2babaae2e4e2bf775960
Date: Fri May 10 15:08:12 2013
EcryptfsInUse: Yes
HibernationDevice: RESUME=UUID=c1607e74-253f-4660-bdb7-45f46947f909
Lsusb:
 Bus 001 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub
 Bus 002 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
 Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
 Bus 001 Device 003: ID 064e:a103 Suyin Corp. Acer/HP Integrated Webcam [CN0314]
MachineType: Gateway NV79
MarkForUpload: True
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.8.0-19-generic root=UUID=da8a8682-2f9b-4878-8b46-6d23657e2137 ro quiet splash acpi_backlight=vendor vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.8.0-19-generic N/A
 linux-backports-modules-3.8.0-19-generic N/A
 linux-firmware 1.106
SourcePackage: linux
UpgradeStatus: Upgraded to raring on 2013-04-26 (14 days ago)
dmi.bios.date: 04/25/2011
dmi.bios.vendor: Gateway
dmi.bios.version: V1.08
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: NV79
dmi.board.vendor: Gateway
dmi.board.version: V1.08
dmi.chassis.type: 10
dmi.chassis.vendor: Gateway
dmi.chassis.version: V1.08
dmi.modalias: dmi:bvnGateway:bvrV1.08:bd04/25/2011:svnGateway:pnNV79:pvrV1.08:rvnGateway:rnNV79:rvrV1.08:cvnGateway:ct10:cvrV1.08:
dmi.product.name: NV79
dmi.product.version: V1.08
dmi.sys.vendor: Gateway

[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 v3.9 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/v3.9-saucy/

[Ethan Shalev (shalev-ethan)]

Tested with kernel 3.9. Problem exists there too.

[Launchpad Janitor (janitor)]

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

[Ethan Shalev (shalev-ethan)]

I upgraded to Saucy, running 3.11, and this bug persists.

[Ethan Shalev (shalev-ethan)]

Christopher M. Penalver, thanks for your clear instructions.
I tested with linux-image-3.12.0-031200rc6-generic, and this problem persists.
I also found that when booting the machine, I can adjust the brightness when GRUB2 is loaded, and then when I boot into Ubuntu, I'm stuck at whatever brightness level I had in GRUB2.

Good hunting, and thanks!
I'll be happy to offer any more information you might need.

[Ethan Shalev (shalev-ethan)]

I just installed a fresh install of 13.10 on this machine, and the problem persisted. However, changing my GRUB settings to
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX="acpi_osi=Linux"
now allows me to adjust the brightness, although at boot, it's set to 0. (I'll look into that problem seperately).
Is there any reason I should not use acpi_osi=Linux? I've read it could have ill effect, namely on the fans. Can I test this somehow?

Does this information help in somehow fixing this problem for other users?

[penalvch (penalvch)]

Ethan Shalev, if for any reason you encounter any potential collateral issues from acpi_osi=Linux, you could try using a different debug kernel parameter:
acpi_backlight=vendor

Despite this, could you please undo any WORKAROUNDs, and test the latest mainline kernel via http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.13-rc2-trusty/ and advise on the results?

[Launchpad Janitor (janitor)]

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