Workaround information
Reboot with only the kernel parameter acpi_backlight=vendor :
no change
output of ls /sys/class/backlight
ideapad
intel_backlight
thinkpad_screen
output of ls -la /sys/class/backlight/intel_backlight/ > lslabacklight
as root
total 0
drwxr-xr-x 3 root root 0 Aug 8 23:17 .
drwxr-xr-x 4 root root 0 Aug 8 23:17 ..
-r--r--r-- 1 root root 4096 Aug 8 23:27 actual_brightness
-rw-r--r-- 1 root root 4096 Aug 8 23:27 bl_power
-rw-r--r-- 1 root root 4096 Aug 8 23:17 brightness
lrwxrwxrwx 1 root root 0 Aug 8 23:27 device -> ../../card0-LVDS-1
-r--r--r-- 1 root root 4096 Aug 8 23:17 max_brightness
drwxr-xr-x 2 root root 0 Aug 8 23:27 power
lrwxrwxrwx 1 root root 0 Aug 8 23:27 subsystem ->
../../../../../../../class/backlight
-r--r--r-- 1 root root 4096 Aug 8 23:17 type
-rw-r--r-- 1 root root 4096 Aug 8 23:17 uevent
echo 8 > /sys/class/backlight/intel_backlight/brightness
brightness changes
reboot with just kernel parameter video.use_native_backlight=1
keys still cannot be used for changing brightness
creating a new file in /usr/share/X11/xorg.conf.d/80-backlight.conf and
paste into it the following code:
Section "Device"
Identifier "Intel Graphics"
Driver "intel"
Option "AccelMethod" "sna"
Option "Backlight" "intel_backlight" # use your backlight that
works here
BusID "PCI:0:2:0"
EndSection
keys can now be used for changing brightness of backlight
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You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux in Ubuntu.
https://bugs.launchpad.net/bugs/1354710
Title:
Backlight control does not work, but there are entries in
/sys/class/backlight.
Status in “linux” package in Ubuntu:
New
Bug description:
Laptop model: Lenovo B570
package version: Ubuntu 3.13.0-32.57-generic 3.13.11.4
I expected the keys for changeing the backlight brightness to work
they had no effect on the backlight
further details in attatched Tar
ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-3.13.0-32-generic 3.13.0-32.57
ProcVersionSignature: Ubuntu 3.13.0-32.57-generic 3.13.11.4
Uname: Linux 3.13.0-32-generic i686
ApportVersion: 2.14.1-0ubuntu3.3
Architecture: i386
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC0: x321x321 1977 F.... pulseaudio
Date: Sat Aug 9 16:11:34 2014
HibernationDevice: RESUME=UUID=61c2c6a6-4b45-4af0-941a-dadf05ad0aba
InstallationDate: Installed on 2014-07-31 (8 days ago)
InstallationMedia: Xubuntu 14.04.1 LTS "Trusty Tahr" - Release i386 (20140723)
MachineType: LENOVO 1068FJG
ProcEnviron:
LANGUAGE=en_GB:en
TERM=xterm
PATH=(custom, no user)
LANG=en_GB.UTF-8
SHELL=/bin/bash
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.13.0-32-generic
root=/dev/mapper/xubuntu--vg-root ro quiet splash vt.handoff=7
PulseList:
Error: command ['pacmd', 'list'] failed with exit code 1: Home directory not
accessible: Permission denied
No PulseAudio daemon running, or not running as session daemon.
RelatedPackageVersions:
linux-restricted-modules-3.13.0-32-generic N/A
linux-backports-modules-3.13.0-32-generic N/A
linux-firmware 1.127.5
SourcePackage: linux
StagingDrivers: rts5139
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 07/11/2011
dmi.bios.vendor: LENOVO
dmi.bios.version: 44CN36WW
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:bvr44CN36WW:bd07/11/2011:svnLENOVO:pn1068FJG:pvrLenovoB570:rvnLENOVO:rnEmeraldLake:rvrFAB1:cvnLENOVO:ct10:cvr0.1:
dmi.product.name: 1068FJG
dmi.product.version: Lenovo B570
dmi.sys.vendor: LENOVO
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