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<base href="https://bugs.freedesktop.org/" />
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<th>Priority</th>
<td>medium
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</tr>
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - [radeon regression] Backlight turned off since kernel upgrade"
href="https://bugs.freedesktop.org/show_bug.cgi?id=83460">83460</a>
</td>
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<th>Assignee</th>
<td>dri-devel@lists.freedesktop.org
</td>
</tr>
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<th>Summary</th>
<td>[radeon regression] Backlight turned off since kernel upgrade
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Classification</th>
<td>Unclassified
</td>
</tr>
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<th>OS</th>
<td>Linux (All)
</td>
</tr>
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<th>Reporter</th>
<td>spmf2004-freedesktop@yahoo.fr
</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>
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<th>Version</th>
<td>XOrg CVS
</td>
</tr>
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<th>Component</th>
<td>DRM/Radeon
</td>
</tr>
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<th>Product</th>
<td>DRI
</td>
</tr></table>
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<pre>Since the upgrade to Ubuntu kernel 3.13.0-35 (from 3.13.0-34), the screen is
very dark to the point it's unusable.
Backlight seems completely turned off. Using the brightness keys doesn't help.
It was working fine with 3.13.0-34.
I found that the offending patch is "drm/radeon: set default bl level to
something reasonable".
I reverted this patch and recompiled 3.13.0-35, and it solved the problem.
I also checked that this problem also affects mainline kernel 3.17rc3.
More technical details can be found on Ubuntu's bugtracker :
<a href="https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1364148">https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1364148</a></pre>
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</p>
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