Bug 845077

Summary: Dell XPS 13: Backlight Brightness Controls Not Working
Product: [Fedora] Fedora Reporter: Lorenzo Villani <lorenzo>
Component: kernelAssignee: Kernel Maintainer List <kernel-maint>
Status: CLOSED UPSTREAM QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: medium Docs Contact:
Priority: unspecified    
Version: 16CC: gansalmon, itamar, jforbes, jonathan, kernel-maint, madhu.chinakonda, rolle.hoffmann
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Hardware: Unspecified   
OS: Unspecified   
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Fixed In Version: Doc Type: Bug Fix
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Last Closed: 2012-08-17 21:48:48 UTC Type: Bug
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description Flags
[PATCH 1/4] drm/i915: pnv has a backlight polarity control bit, too
none
[PATCH 2/4] drm/i915: clear up backlight #define confusion on gen4+ none

Description Lorenzo Villani 2012-08-01 16:43:15 UTC 
Description of problem:
Brightness controls on Dell XPS 13 don't work.

There's a patch set available at http://lists.freedesktop.org/archives/intel-gfx/2012-June/018030.html which solves the issue (tested with a locally rebuilt kernel RPM which includes said stack of patches).


Version-Release number of selected component (if applicable):
3.4.6-1


How reproducible:
Always


Steps to Reproduce:
1. Press Fn+F4 or Fn+F5 to decrease/increase the panel brightness;


Actual results:
Panel brightness doesn't change (although Gnome shows the display brightness popup).


Expected results:
Panel brightness should increase and decrease as I press the buttons.


Additional info:
It is possible to work-around the problem by creating an acpid event file like the following:

https://raw.github.com/lvillani/post-install/078d47358be70d23d4edc93eea527a4898175e50/files/acpi/intel_workaround
Comment 1 Lorenzo Villani 2012-08-01 16:47:57 UTC 
Created attachment 601782 [details]
[PATCH 1/4] drm/i915: pnv has a backlight polarity control bit, too
Comment 2 Lorenzo Villani 2012-08-01 16:50:12 UTC 
Created attachment 601783 [details]
[PATCH 2/4] drm/i915: clear up backlight #define	confusion on gen4+
Comment 3 Lorenzo Villani 2012-08-01 17:35:50 UTC 
Oh wait... looks like these patches were merged in 3.5.0. I'm rebuilding my customized kernel RPMs (which include other patches for my Dell XPS 13) in order to test it.
Comment 4 Lorenzo Villani 2012-08-03 14:02:55 UTC 
I'm now running kernel-3.6.0-0.rc0.git9.3.fc18.x86_64 and the issue seems to be fixed.

Can the patch-set be backported to F-16 and F-17 kernels?
Comment 5 Justin M. Forbes 2012-08-17 21:48:48 UTC 
The 3.5 kernels are coming to F16 soon, we have one major issue that F17 users are experiencing that we need to get fixed first.
Comment 6 Rolle 2013-11-08 10:41:07 UTC 
With kernel 3.10 and 3.11 (actually until fedora kernel 3.11.7) it doesn't work for anymore. See Bug Report 1028383 and Bug Report 995782.
Comment 7 Rolle 2013-11-08 10:41:42 UTC 
Comment 6 was tried with Fedora 20 alpha