regression: linux-image 2.6.28-15.51 in jaunty-proposed breaks brightness control of T500
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Invalid
|
Medium
|
Unassigned | ||
Jaunty |
Fix Released
|
Medium
|
Stefan Bader |
Bug Description
SRU Justification:
Impact: The patch which tried to solve bug #228399 contained a glitch which caused regressions for a certain set of Intel video cards.
Fix: Reverted the patch
Testcase: Booting with the affected kernel causes the acpi video driver not to be initialized and this no backlight control.
---
linux-image 2.6.28-15.51 in jaunty-proposed breaks brightness control of (at least) Lenovo Thinkpad T500.
Verified with two T500 with different BIOS versions.
The directory /proc/acpi/video is missing, and thus brightness control with brightness buttons
is broken.
Workaround:
boot 2.6.28-15.49 from jaunty-
Infos about breaking kernel:
1.) uname -a
Linux titan 2.6.28-15-generic #51-Ubuntu SMP Mon Aug 31 13:33:16 UTC 2009 i686 GNU/Linux
2.) cat /proc/version_
Ubuntu 2.6.28-
Sidenote: dmesg says this for both! kernels
thinkpad_acpi: This ThinkPad has standard ACPI backlight brightness control, supported by the ACPI video driver
Best regards,
Arnd
tags: | added: regression-update |
Changed in linux (Ubuntu): | |
importance: | Undecided → Medium |
status: | New → Triaged |
tags: |
added: regression-proposed removed: regression-update |
this regression also affects thinkpad sl series