Regression in brightness control on Lenovo Thinkpad X230 (+tablet) and X1 Carbon
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
Linux |
Fix Released
|
Medium
|
|||
linux (Fedora) |
Fix Released
|
High
|
|||
linux (Ubuntu) |
Triaged
|
Medium
|
Seth Forshee |
Bug Description
== Raring SRU Justification ==
Impact: A number of ThinkPad models have a workaround in the ACPI
backlight implementation for Windows 8 that more or less completely
breaks backlight control.
Fix: Add an OSI quirk to no longer claim to be Windows 8 on these
machines, causing the firmware to revert to the older, working behavior.
Test Case: Verified on LP #1098216 and bugzill.kernel.org #51231.
---
Something changed between the 3.5 and the 3.7 kernel, leading to broken brightness control on my Thinkpad x230.
Here are some test results:
== 3.5.0-21-generic ==
=== Post-boot values ===
/sys/class/
- intel-backlight
+ actual_brightness => 4438
+ bl_power => 0
+ brightness => 4438
+ max_brightness => 4438
- acpi_video0
+ actual_brightness => 15
+ bl_power => 0
+ brightness => 15
+ max_brightness => 15
=== Tests ===
echo 0 > acpi_video0/
echo 0 > intel_backlight
== 3.8.0-0-generic ==
=== Post-boot values ===
/sys/class/
- intel-backlight
+ actual_brightness => 4438
+ bl_power => 0
+ brightness => 4438
+ max_brightness => 4438
- acpi_video0
+ actual_brightness => 100
+ bl_power => 0
+ brightness => 100
+ max_brightness => 100
=== Tests ===
echo 0 > acpi_video0/
echo 0 > intel_backlight
---
ApportVersion: 2.8-0ubuntu1
Architecture: amd64
CheckboxSubmission: 12108b8b8b67d76
CheckboxSystem: bb422ca46d02494
DistroRelease: Ubuntu 13.04
InstallationDate: Installed on 2012-09-02 (129 days ago)
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Alpha amd64 (20120902)
MarkForUpload: True
Package: linux (not installed)
ProcEnviron:
LANGUAGE=en_US:en
TERM=xterm
PATH=(custom, no user)
LANG=en_US.UTF-8
SHELL=/bin/bash
ProcVersionSign
Tags: raring
Uname: Linux 3.8.0-0-generic x86_64
UnreportableReason: The running kernel is not an Ubuntu kernel
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups:
WORKAROUND:
Add to /etc/default/grub
in the variable "GRUB_CMDLINE_
acpi_osi=\"!Windows 2012\"
e.g:
GRUB_CMDLINE_
Then run "sudo update-grub".
Changed in linux: | |
importance: | Unknown → Medium |
status: | Unknown → Incomplete |
tags: | removed: performing-bisect |
tags: | added: patch |
description: | updated |
description: | updated |
description: | updated |
summary: |
- Regression in brightness control on Lenovo Thinkpad X230 and X1 Carbon + Regression in brightness control on Lenovo Thinkpad X230 (+tablet) and + X1 Carbon |
tags: | added: verification-needed-raring |
tags: |
added: verification-done removed: verification-needed-raring |
Changed in linux: | |
status: | Incomplete → In Progress |
Changed in linux: | |
status: | In Progress → Incomplete |
Changed in linux: | |
status: | Incomplete → In Progress |
tags: | added: trusty |
Changed in linux (Fedora): | |
importance: | Unknown → High |
status: | Unknown → Fix Released |
Changed in linux: | |
status: | In Progress → Fix Released |
This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:
apport-collect 1098216
and then change the status of the bug to 'Confirmed'.
If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.
This change has been made by an automated script, maintained by the Ubuntu Kernel Team.