FS#33177 - [linux] 3.7 Unable to change brightness

Attached to Project: Arch Linux
Opened by Michael Werner (Xaseron) - Sunday, 23 December 2012, 13:09 GMT
Last edited by Tobias Powalowski (tpowa) - Wednesday, 27 February 2013, 11:22 GMT
Task Type Bug Report
Category Kernel
Status Closed
Assigned To Tobias Powalowski (tpowa)
Thomas Bächler (brain0)
Architecture All
Severity High
Priority Normal
Reported Version
Due in Version Undecided
Due Date Undecided
Percent Complete 100%
Votes 1
Private No

Details

Description:
I can't change the brightness with hardware buttons anymore.
I can echo values to /sys/class/backlight/acpi_video0/brightness but this doesn't have any effect.


Additional info:
Linux 3.7.1-2
ThinkPad X230
This task depends upon

Closed by  Tobias Powalowski (tpowa)
Wednesday, 27 February 2013, 11:22 GMT
Reason for closing:  Fixed
Additional comments about closing:  Fixes are posted below.
Comment by Daniel Kao (dkao) - Sunday, 30 December 2012, 11:56 GMT
Upstream bug: https://bugzilla.kernel.org/show_bug.cgi?id=51231

At the moment I have a rather ugly workaround: add acpi_osi=Linux acpi_backlight=vendor thinkpad_acpi.brightness_enable=0 to your kernel commandline.
The acpi_backlight=vendor will allow hardware buttons to adjust backlight. thinkpad_acpi.brightness_enable=0 will make intel_backlight the only backlight device, so it gets picked up by gnome-settings-daemon despite gsd's firmware > platform > raw backlight type preference.
Comment by Daniel Kao (dkao) - Monday, 31 December 2012, 09:18 GMT
acpi_osi="!Windows 2012" ended up fixing this for me, also on ThinkPad X230.
Comment by Edward O'Callaghan (evocallaghan) - Tuesday, 22 January 2013, 07:51 GMT
Confirmed as a regression on my Lenovo T530.

I added

# Increase screen brightness (Fn+F9)
"xbacklight -inc 10"
XF86MonBrightnessUp

# Decrease screen brightness (Fn+F8)
"xbacklight -dec 10"
XF86MonBrightnessDown

to .xbindkeysrc to get it working. I did not need this before I upgraded to Linux dexter 3.7.3-1-ARCH #1 SMP PREEMPT Thu Jan 17 18:52:30 CET 2013 x86_64 GNU/Linux

Regards,
Edward.
Comment by Christoph Vigano (kritztopf) - Sunday, 27 January 2013, 00:04 GMT
The following workaround works now for me:

1.) Add acpi_backlight=vendor to kernel commandline
2.) Add "options thinkpad_acpi brightness_enable=1" to /etc/modprobe.d/thinkpad_acpi.conf

Took me a week to workaround this one... now my function keys for brightness are working again everywhere

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