I've tested it with v4.4-rc4-wily, and the bug does not exist, leaving
only intel_backlight with the default GRUB configuration (no extra
options except "quiet splash").
While installing the upstream kernel, though, there was a warning:
W: Possible missing firmware /lib/firmware/i915/skl_guc_ver4.bin for
module i915
** Tags removed: kernel-bug-exists-upstream
** Tags added: kernel-bug-fixed-upstream kernel-bug-fixed-upstream-4.4-rc4
** Changed in: linux (Ubuntu)
Status: Incomplete => Confirmed
** Tags added: wily
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https://bugs.launchpad.net/bugs/1486896
Title:
On Lenovo Thinkpad Edge E330, the screen backlight flickers badly.
Status in linux package in Ubuntu:
Confirmed
Bug description:
Behavior is the same on Ubuntu 14.04 -- 15.04.
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.
Old workaround: If no changes are made to boot options, and
echo 4437 > /sys/class/backlight/intel_backlight/brightness
is done, the flicker stops and the GUI control / acpi_video0 works, but
causes flicker again.
Workaround 2: Kernel parameters: "thinkpad-acpi.brightness_enable=0
acpi_backlight=vendor" fully fix the bug behavior and retain the
brightness control.
Issue: the intel_backlight device should be used, the workaround above
disables the other devices, leaving only one, thus no conflicts occur.
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
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