Screen Brightness keys do not work on Lenovo IdeaPad Z570

[sebastian-s]

I've installed 14.04 from scratch but had this issue under 13.10 too.

The key combination Fn+<brightness up/down> trigger the brightness overlay in the top right corner but the actual brightness does not change. See attached screenshot

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-3.13.0-29-generic 3.13.0-29.53
ProcVersionSignature: Ubuntu 3.13.0-29.53-generic 3.13.11.2
Uname: Linux 3.13.0-29-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.2
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: seb 1951 F.... pulseaudio
 /dev/snd/pcmC0D0p: seb 1951 F...m pulseaudio
CurrentDesktop: Unity
Date: Wed Jun 18 22:25:22 2014
EcryptfsInUse: Yes
InstallationDate: Installed on 2014-06-14 (3 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64+mac (20140417)
MachineType: LENOVO 10247MM
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-29-generic root=UUID=4424b647-bd6c-425e-bc1f-a170d430217d ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.13.0-29-generic N/A
 linux-backports-modules-3.13.0-29-generic N/A
 linux-firmware 1.127.2
SourcePackage: linux
StagingDrivers: rts5139
UpgradeStatus: No upgrade log present (probably fresh install)
WifiSyslog:

dmi.bios.date: 10/21/2011
dmi.bios.vendor: LENOVO
dmi.bios.version: 45CN38WW
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: Emerald Lake
dmi.board.vendor: LENOVO
dmi.board.version: FAB1
dmi.chassis.asset.tag: Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: 0.1
dmi.modalias: dmi:bvnLENOVO:bvr45CN38WW:bd10/21/2011:svnLENOVO:pn10247MM:pvrIdeapadZ570:rvnLENOVO:rnEmeraldLake:rvrFAB1:cvnLENOVO:ct10:cvr0.1:
dmi.product.name: 10247MM
dmi.product.version: Ideapad Z570
dmi.sys.vendor: LENOVO

[sebastian-s (sebastian-s)]

I can change the brightness by
$ echo 100 | sudo tee /sys/class/backlight/intel_backlight/brightness

[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 v3.16 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/v3.16-rc1-utopic/

[sebastian-s (sebastian-s)]

Hi, I've tested with
3.16.0-031600rc1-generic #201406160035 SMP Mon Jun 16 04:36:15 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
with the same result. The overlay is shown and changes the brightness scale but not the actual screen brightness

[madbiologist (me-again)]

This might be fixed in the upcoming 3.18 kernel by this patch:

Stepan Bujnak:
ACPI / video: force vendor backlight on Lenovo Ideapad Z570

[madbiologist (me-again)]

There is a better fix queued up for the upstream 4.1 kernel. It consists of these two patches:

acpi: video: Allow forcing native backlight on non win8 machines
acpi: video: Add enable native backlight quirk for Lenovo Ideapad Z570