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<base href="https://bugs.freedesktop.org/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - FBC on HD4600 causes screen flickering on certain screen content"
href="https://bugs.freedesktop.org/show_bug.cgi?id=92874">92874</a>
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<th>Summary</th>
<td>FBC on HD4600 causes screen flickering on certain screen content
</td>
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<th>Product</th>
<td>DRI
</td>
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<th>Version</th>
<td>unspecified
</td>
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<th>Hardware</th>
<td>Other
</td>
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<th>OS</th>
<td>All
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>medium
</td>
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<th>Component</th>
<td>DRM/Intel
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<th>Assignee</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
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<th>Reporter</th>
<td>brain@jikos.cz
</td>
</tr>
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<th>QA Contact</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
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<th>CC</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
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<p>
<div>
<pre>Machine: Asus "Zenbook" UX501
CPU: i7 4720HQ
GPU: Intel HD4600
Kernel 4.3.2
OS: Kubuntu 15.10
After enabling FBC with kernel option "i915.enable_fbc=1" the screen flickers
with specific video content. Typically Firefox browser with some page. As an
example the "<a href="https://01.org/linuxgraphics/community/kernel">https://01.org/linuxgraphics/community/kernel</a>" at the default zoom
level.
Please note that my notebook has 4k display. I have seen the issue only on the
built-in panel, not on an external screen.
The flickering typically looks like the picture is switching between correct
look and the same picture shifted down. The Y offset varies depending on the
content. So does the flickering frequency. In the above example the offset is
about half of the screen height.
If the content changes, e.g. change the zoom level in Firefox (on the above
example it's sufficient to scroll down to the text so the picture disappears),
the flickering changes or disappears.</pre>
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