[Lenovo V480] Unable to control the brightness from Max - Min
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux-lts-trusty (Ubuntu) |
Triaged
|
Medium
|
Unassigned |
Bug Description
CID: 201204-10924 Lenovo V480
With the Brightness applet, the brightness level on this system cannot be adjusted from Max (let's say, level 11) to Min (level 1).
The brightness level will goes down and up, which behaves like 11-10-9-
Steps:
1. Install 12.04.3 + update (3.8.0-33), boot to desktop
2. Adjust the screen brightness by the Brightness and Lock applet, clicking the leftmost part of the scroll bar to change the brightness stepwise
3. Click and drag the slider to adjust the brightness
Expected result:
- Brightness could be adjusted smoothly.
Actual result:
1. Brightness cannot go down to the lowest level, it behaves like 11-10-9-
2. When you drag and move the slider, the backlight will flash between Max and the indicated level.
Debugging information:
$ ls /sys/class/
acpi_video0@ intel_backlight@
$ dmesg | grep 'ACPI: Video'
[ 7.104361] ACPI: Video Device [PEGP] (multi-head: no rom: yes post: no)
[ 7.107524] ACPI: Video Device [GFX0] (multi-head: yes rom: no post: no)
$ cat /proc/version
Linux version 3.8.0-33-generic (buildd@toyol) (gcc version 4.6.3 (Ubuntu/Linaro 4.6.3-1ubuntu5) ) #48~precise1-Ubuntu SMP Thu Oct 24 16:28:06 UTC 2013
Note: the hotkey is probably affected by bug 1248442, but it will cause the same result when it's working.
ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: linux-image-
ProcVersionSign
Uname: Linux 3.8.0-33-generic x86_64
AlsaVersion: Advanced Linux Sound Architecture Driver Version k3.8.0-33-generic.
ApportVersion: 2.0.1-0ubuntu17.6
Architecture: amd64
ArecordDevices:
**** List of CAPTURE Hardware Devices ****
card 0: PCH [HDA Intel PCH], device 0: ALC269VC Analog [ALC269VC Analog]
Subdevices: 1/1
Subdevice #0: subdevice #0
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/
CRDA: Error: [Errno 2] No such file or directory
Card0.Amixer.info:
Card hw:0 'PCH'/'HDA Intel PCH at 0xf3610000 irq 47'
Mixer name : 'Intel PantherPoint HDMI'
Components : 'HDA:10ec0269,
Controls : 29
Simple ctrls : 11
Card29.Amixer.info:
Card hw:29 'ThinkPadEC'
Mixer name : 'ThinkPad EC (unknown)'
Components : ''
Controls : 1
Simple ctrls : 1
Card29.
Simple mixer control 'Console',0
Capabilities: pswitch pswitch-joined penum
Playback channels: Mono
Mono: Playback [on]
Date: Tue Nov 26 01:10:44 2013
HibernationDevice: RESUME=
InstallationMedia: Ubuntu 12.04.3 LTS "Precise Pangolin" - Release amd64 (20130820.1)
MachineType: LENOVO 814TD01
MarkForUpload: True
ProcEnviron:
TERM=xterm
PATH=(custom, no user)
LANG=en_US.UTF-8
SHELL=/bin/bash
ProcFB:
0 inteldrmfb
1 nouveaufb
ProcKernelCmdLine: BOOT_IMAGE=
RelatedPackageV
linux-
linux-
linux-firmware 1.79.7
SourcePackage: linux-lts-raring
StagingDrivers: keucr
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 04/10/2013
dmi.bios.vendor: LENOVO
dmi.bios.version: H5ET73WW(1.16)
dmi.board.
dmi.board.name: 814TD01
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.
dmi.modalias: dmi:bvnLENOVO:
dmi.product.name: 814TD01
dmi.product.
dmi.sys.vendor: LENOVO
Changed in linux-lts-raring (Ubuntu): | |
assignee: | Anthony Wong (anthonywong) → Alex Hung (alexhung) |
status: | New → Triaged |
Changed in linux-lts-raring (Ubuntu): | |
status: | Triaged → In Progress |
Changed in linux-lts-raring (Ubuntu): | |
assignee: | Alex Hung (alexhung) → Anthony Wong (anthonywong) |
Changed in linux-lts-raring (Ubuntu): | |
importance: | Undecided → Medium |
Changed in linux-lts-raring (Ubuntu): | |
status: | Triaged → Incomplete |
status: | Incomplete → Triaged |
tags: | added: latest-bios-1.16 |
affects: | linux-lts-raring (Ubuntu) → linux-lts-trusty (Ubuntu) |
after adding "acpi_backlight =vendor" to grub
the hotkey works fine, but the brightness level indicator won't pop-out
and the Brightness applet become not working at all, brightness won't change when you try to adjust it.
Debuggung information: backlight
$ ls /sys/class/
intel_backlight thinkpad_screen
# ls -la /sys/class/ backlight/ intel_backlight backlight/ intel_backlight -> ../../devices/ pci0000: 00/0000: 00:02.0/ drm/card0/ card0-LVDS- 1/intel_ backlight
lrwxrwxrwx 1 root root 0 Nov 26 04:54 /sys/class/
Brightness will change to very low with backlight/ intel_backlight /brightness
echo 8 > /sys/class/