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<base href="https://bugs.freedesktop.org/" />
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<th>Priority</th>
<td>medium
</td>
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<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - [PATCH] get intel_backlight back into backlight_interfaces"
href="https://bugs.freedesktop.org/show_bug.cgi?id=71493">71493</a>
</td>
</tr>
<tr>
<th>Keywords</th>
<td>regression
</td>
</tr>
<tr>
<th>Assignee</th>
<td>chris@chris-wilson.co.uk
</td>
</tr>
<tr>
<th>Summary</th>
<td>[PATCH] get intel_backlight back into backlight_interfaces
</td>
</tr>
<tr>
<th>QA Contact</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux (All)
</td>
</tr>
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<th>Reporter</th>
<td>mike@altlinux.org
</td>
</tr>
<tr>
<th>URL</th>
<td>http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=651741
</td>
</tr>
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<th>Hardware</th>
<td>x86-64 (AMD64)
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Version</th>
<td>git
</td>
</tr>
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<th>Component</th>
<td>Driver/intel
</td>
</tr>
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<th>Product</th>
<td>xorg
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=89029" name="attach_89029" title="get intel_backlight back into backlight_interfaces (uses to just work)">attachment 89029</a> <a href="attachment.cgi?id=89029&action=edit" title="get intel_backlight back into backlight_interfaces (uses to just work)">[details]</a></span> <a href='page.cgi?id=splinter.html&bug=71493&attachment=89029'>[review]</a>
get intel_backlight back into backlight_interfaces (uses to just work)
xf86-video-intel commit ce1e0969058f8c70b624bc85bb8d6698a35794d3 broke
backlight controls for me when using Linux 3.7+, recent xorg and e17 on ASUS
UX31A (that's HD4000 within i7-3517U).
What works: writing to /sys/class/backlight/intel_backlight/brightness
What doesn't: writing to /sys/class/backlight/acpi_video0/brightness
(actual_brightness returns 94 or 95 with no correlation).
The problem is that xorg prefers acpi_video0 since that commit.
Booting with acpi_backlight=vendor results in /sys/class/backlight/acpi_video0/
being replaced by /sys/class/backlight/asus-nb-wmi/ with actual_brightness
value being constant 100 and writes to brightness resulting in no-op.
I have to maintain local fork of the package with the attached patch merged
into it.
Another known workaround is:
---
Section "Device"
Identifier "Intel Graphics"
Driver "intel"
Option "Backlight" "intel_backlight"
EndSection
--- /etc/X11/xorg.conf.d/99-intel-backlight.conf
Wonder why intel_backlight was dropped from the list in the first place as it's
known to just work on various intel videochips here so far.</pre>
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