Public bug reported:
With yakkety's recent update from linux 4.4 to 4.8 my brightness keys
stopped working. They are not handled in software via evdev events (on
most platforms you just get a KEY_BRIGHTNESS{UP<DOWN}), but are
hardwired in the kernel driver.
With both 4.4 and 4.8 dmesg shows:
[ 10.114072] thinkpad_acpi: This ThinkPad has standard ACPI backlight
brightness control, supported by the ACPI video driver
[ 10.114073] thinkpad_acpi: Disabling thinkpad-acpi brightness events by
default...
In 4.4 I have these two devices in /sys:
/sys/class/backlight/acpi_video0/:
-r--r--r-- 1 root root 4096 Sep 22 09:45 actual_brightness
-rw-r--r-- 1 root root 4096 Sep 22 09:45 bl_power
-rw-r--r-- 1 root root 4096 Sep 22 09:45 brightness
lrwxrwxrwx 1 root root 0 Sep 22 09:45 device -> ../../../0000:00:02.0
-r--r--r-- 1 root root 4096 Sep 22 09:45 max_brightness
drwxr-xr-x 2 root root 0 Sep 22 09:45 power
lrwxrwxrwx 1 root root 0 Sep 22 09:45 subsystem ->
../../../../../class/backlight
-r--r--r-- 1 root root 4096 Sep 22 09:45 type
-rw-r--r-- 1 root root 4096 Sep 22 09:45 uevent
/sys/class/backlight/intel_backlight/:
-r--r--r-- 1 root root 4096 Sep 22 09:46 actual_brightness
-rw-r--r-- 1 root root 4096 Sep 22 09:46 bl_power
-rw-r--r-- 1 root root 4096 Sep 22 09:46 brightness
lrwxrwxrwx 1 root root 0 Sep 22 09:46 device -> ../../card0-LVDS-1
-r--r--r-- 1 root root 4096 Sep 22 09:46 max_brightness
drwxr-xr-x 2 root root 0 Sep 22 09:46 power
lrwxrwxrwx 1 root root 0 Sep 22 09:46 subsystem ->
../../../../../../../class/backlight
-r--r--r-- 1 root root 4096 Sep 22 09:46 type
-rw-r--r-- 1 root root 4096 Sep 22 09:46 uevent
While in 4.8 I only have intel_backlight and acpi_video0 is missing
completely.
I. e. in 4.4 this command works:
echo 12 | sudo tee /sys/class/backlight/acpi_video0/brightness
and I suppose this is the moral equivalent of what happens when I press
the brightness keys, i. e. these keys seem to be handled by the
acpi_video0 driver instead of intel_backlight.
The intel driver still actually works, I can do
echo 1000 | sudo tee /sys/class/backlight/intel_backlight/brightness
but this isn't connected to the keys any more.
ProblemType: Bug
DistroRelease: Ubuntu 16.10
Package: linux-image-4.8.0-11-generic 4.8.0-11.12
ProcVersionSignature: Ubuntu 4.8.0-11.12-generic 4.8.0-rc6
Uname: Linux 4.8.0-11-generic x86_64
ApportVersion: 2.20.3-0ubuntu7
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/pcmC0D0c: martin 3049 F...m pulseaudio
/dev/snd/pcmC0D0p: martin 3049 F...m pulseaudio
/dev/snd/controlC0: martin 3049 F.... pulseaudio
Date: Thu Sep 22 09:42:56 2016
EcryptfsInUse: Yes
MachineType: LENOVO 2324CTO
ProcEnviron:
TERM=linux
PATH=(custom, no user)
XDG_RUNTIME_DIR=<set>
LANG=de_DE.UTF-8
SHELL=/bin/bash
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/@/boot/vmlinuz-4.8.0-11-generic.efi.signed
root=UUID=f86539b0-3a1b-4372-83b0-acdd029ade68 ro rootflags=subvol=@
systemd.debug-shell
RelatedPackageVersions:
linux-restricted-modules-4.8.0-11-generic N/A
linux-backports-modules-4.8.0-11-generic N/A
linux-firmware 1.161
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 07/09/2013
dmi.bios.vendor: LENOVO
dmi.bios.version: G2ET95WW (2.55 )
dmi.board.asset.tag: Not Available
dmi.board.name: 2324CTO
dmi.board.vendor: LENOVO
dmi.board.version: 0B98401 Pro
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias:
dmi:bvnLENOVO:bvrG2ET95WW(2.55):bd07/09/2013:svnLENOVO:pn2324CTO:pvrThinkPadX230:rvnLENOVO:rn2324CTO:rvr0B98401Pro:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 2324CTO
dmi.product.version: ThinkPad X230
dmi.sys.vendor: LENOVO
** Affects: linux (Ubuntu)
Importance: Undecided
Status: Confirmed
** Tags: amd64 apport-bug regression-release yakkety
** Tags added: regression-release
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https://bugs.launchpad.net/bugs/1626429
Title:
[4.8 regression][ThinkPad X230] brightness change keys do not work any
more
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