Public bug reported:
Steps were taken according to this:
https://wiki.ubuntu.com/Kernel/Debugging/Backlight
With acpi_backlight=vendor, the flicker stops, and the brightness control
doesn't work.
However,
echo 8 > /sys/class/backlight/intel_backlight/brightness
dims the screen.
thinkpad-acpi.brightness_enable = 1 does nothing.
But if no changes are made, and
echo 4437 > /sys/class/backlight/intel_backlight/brightness
is done, the flicker stops and the GUI control / acpi_video0 works.
Attaching the necessary files.
ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: linux-image-3.19.0-26-generic 3.19.0-26.28
ProcVersionSignature: Ubuntu 3.19.0-26.28-generic 3.19.8-ckt4
Uname: Linux 3.19.0-26-generic x86_64
ApportVersion: 2.17.2-0ubuntu1.3
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC0: mark 1391 F.... pulseaudio
CurrentDesktop: Unity
Date: Thu Aug 20 11:21:39 2015
HibernationDevice: RESUME=UUID=7a9e1f17-c57b-4e6f-bb0c-0b090b5d1405
InstallationDate: Installed on 2014-08-22 (363 days ago)
InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2)
MachineType: LENOVO 3354DGG
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.19.0-26-generic
root=UUID=b566feb2-5a5c-4573-8782-b78d130dbc45 ro quiet splash
acpi_backlight=vendor vt.handoff=7
RelatedPackageVersions:
linux-restricted-modules-3.19.0-26-generic N/A
linux-backports-modules-3.19.0-26-generic N/A
linux-firmware 1.143.3
SourcePackage: linux
UpgradeStatus: Upgraded to vivid on 2015-08-20 (0 days ago)
dmi.bios.date: 02/25/2013
dmi.bios.vendor: LENOVO
dmi.bios.version: H3ET72WW(1.09)
dmi.board.asset.tag: Not Available
dmi.board.name: 3354DGG
dmi.board.vendor: LENOVO
dmi.board.version: 0B98409 Std
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias:
dmi:bvnLENOVO:bvrH3ET72WW(1.09):bd02/25/2013:svnLENOVO:pn3354DGG:pvrThinkPadEdgeE330:rvnLENOVO:rn3354DGG:rvr0B98409Std:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 3354DGG
dmi.product.version: ThinkPad Edge E330
dmi.sys.vendor: LENOVO
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug vivid
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https://bugs.launchpad.net/bugs/1486896
Title:
On Lenovo Thinkpad Edge E330, the screen backlight flickers badly.
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