Bug 78011 - laptop panel backlight is dropped to 0 when external VGA display is connected
Summary: laptop panel backlight is dropped to 0 when external VGA display is connected
Status: RESOLVED CODE_FIX
Alias: None
Product: Drivers
Classification: Unclassified
Component: Video(DRI - Intel) (show other bugs)
Hardware: x86-64 Linux
: P3 normal
Assignee: Jesse Barnes
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2014-06-16 06:42 UTC by Anton Gubarkov
Modified: 2014-06-16 12:28 UTC (History)
1 user (show)

See Also:
Kernel Version: 3.15.0
Subsystem:
Regression: No
Bisected commit-id:


Attachments
log of external monitor connection with drm.debug=0x4 and module backlight +fpt (68.81 KB, text/plain)
2014-06-16 06:44 UTC, Anton Gubarkov
Details

Description Anton Gubarkov 2014-06-16 06:42:24 UTC
Actual behavior:
Every time I connect an external display, my internal panel brightness is
brought to 0. 

Expected behavior:
The internal panel brightness doesn't change when there is a desktop displayed
on it.
Comment 1 Anton Gubarkov 2014-06-16 06:44:32 UTC
Created attachment 139871 [details]
log of external monitor connection with drm.debug=0x4 and module backlight +fpt
Comment 2 Jani Nikula 2014-06-16 09:09:16 UTC
Please attach dmesg from early boot with drm.debug=0xe module parameter set, exhibiting the problem.

Is this a regression? Did this work in the past?
Comment 3 Hans de Goede 2014-06-16 09:30:34 UTC
This seems to be the same issue as reported here:
https://bugzilla.redhat.com/show_bug.cgi?id=1012674

Which is actually an issue in xf86-video-intel, which has been fixed in the recent 2.99.912 release, please give that version a try.
Comment 4 Anton Gubarkov 2014-06-16 10:12:05 UTC
(In reply to Hans de Goede from comment #3)
> This seems to be the same issue as reported here:
> https://bugzilla.redhat.com/show_bug.cgi?id=1012674
> 
> Which is actually an issue in xf86-video-intel, which has been fixed in the
> recent 2.99.912 release, please give that version a try.

Upgrade of xf86-video-intel package solved my problem indeed. Thank you very much.
Comment 5 Jani Nikula 2014-06-16 12:28:51 UTC
Anton, thanks for the report and testing.

Hans, thanks for your continued help in nailing down the backlight bugs!

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