The brightness control on the Lenovo ThinkPad x220 is no longer working after undocking. It is stuck an the lowest level and can't by changed with the hotkeys. There is /sys/class/backlight/acpi_video0/ which has no effect. The bug occurs when using kernel 3.13 on 12.04 and on 14.04.
WORKAROUND: Set the brightness through /sys/class/backlight/intel_backlight/
The hotkeys are working again after setting the brightness once on the command line.
ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: linux-image-3.13.0-30-generic 3.13.0-30.55~precise1
ProcVersionSignature: Ubuntu 3.13.0-30.55~precise1-generic 3.13.11.2
Uname: Linux 3.13.0-30-generic x86_64
ApportVersion: 2.0.1-0ubuntu17.6
Architecture: amd64
Date: Sun Jul 20 09:39:01 2014
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
MarkForUpload: True
SourcePackage: linux-lts-trusty
UpgradeStatus: No upgrade log present (probably fresh install)
---
AlsaVersion: Advanced Linux Sound Architecture Driver Version k3.13.0-32-generic.
ApportVersion: 2.0.1-0ubuntu17.6
Architecture: amd64
ArecordDevices:
**** List of CAPTURE Hardware Devices ****
card 0: PCH [HDA Intel PCH], device 0: CX20590 Analog [CX20590 Analog]
Subdevices: 1/1
Subdevice #0: subdevice #0
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC0: jo 2697 F.... pulseaudio
CRDA: Error: [Errno 2] No such file or directory
Card0.Amixer.info:
Card hw:0 'PCH'/'HDA Intel PCH at 0xf1520000 irq 45'
Mixer name : 'Intel CougarPoint HDMI'
Components : 'HDA:14f1506e,17aa21da,00100002 HDA:80862805,80860101,00100000'
Controls : 43
Simple ctrls : 12
Card29.Amixer.info:
Card hw:29 'ThinkPadEC'/'ThinkPad Console Audio Control at EC reg 0x30, fw unknown'
Mixer name : 'ThinkPad EC (unknown)'
Components : ''
Controls : 1
Simple ctrls : 1
Card29.Amixer.values:
Simple mixer control 'Console',0
Capabilities: pswitch pswitch-joined penum
Playback channels: Mono
Mono: Playback [on]
DistroRelease: Ubuntu 12.04
HibernationDevice: RESUME=UUID=749609cc-8e4e-491e-9194-cbae6b309e18
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
Lsusb:
Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 004: ID 04f2:b217 Chicony Electronics Co., Ltd
MachineType: LENOVO 4290W1A
MarkForUpload: True
Package: linux (not installed)
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-32-generic root=/dev/mapper/vg_nova-ubuntu ro quiet splash nmi_watchdog=0 vt.handoff=7
ProcVersionSignature: Ubuntu 3.13.0-32.57~precise1-generic 3.13.11.4
RelatedPackageVersions:
linux-restricted-modules-3.13.0-32-generic N/A
linux-backports-modules-3.13.0-32-generic N/A
linux-firmware 1.79.16
RfKill:
0: phy0: Wireless LAN
Soft blocked: no
Hard blocked: no
Tags: precise
Uname: Linux 3.13.0-32-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adbusers adm cdrom dip lpadmin plugdev sambashare sudo vboxusers wireshark www-data
dmi.bios.date: 04/11/2013
dmi.bios.vendor: LENOVO
dmi.bios.version: 8DET68WW (1.38 )
dmi.board.asset.tag: Not Available
dmi.board.name: 4290W1A
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvr8DET68WW(1.38):bd04/11/2013:svnLENOVO:pn4290W1A:pvrThinkPadX220:rvnLENOVO:rn4290W1A:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 4290W1A
dmi.product.version: ThinkPad X220
dmi.sys.vendor: LENOVO
jdillmann, please execute the following in a terminal:
apport-collect 1345499