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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 - Regression: DP outputs out of sync on dual-DP tiled 5k screen"
href="https://bugs.freedesktop.org/show_bug.cgi?id=110671">110671</a>
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<th>Summary</th>
<td>Regression: DP outputs out of sync on dual-DP tiled 5k screen
</td>
</tr>
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<th>Product</th>
<td>DRI
</td>
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<th>Version</th>
<td>DRI git
</td>
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<th>Hardware</th>
<td>x86-64 (AMD64)
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<th>OS</th>
<td>Linux (All)
</td>
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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/AMDgpu
</td>
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<th>Assignee</th>
<td>dri-devel@lists.freedesktop.org
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<th>Reporter</th>
<td>bugs@bzatek.net
</td>
</tr></table>
<p>
<div>
<pre>With kernel 5.1.1 I get corrupted image on my Dell UP2715K screen (again). The
symptomps are similar to the ones in <a class="bz_bug_link
bz_status_NEW "
title="NEW - Radeon and 5k resolution 5120x2880 = corrupted image"
href="show_bug.cgi?id=98461">bug 98461</a> (see also <span class=""><a href="attachment.cgi?id=127570" name="attach_127570" title="Photo of display">attachment 127570</a> <a href="attachment.cgi?id=127570&action=edit" title="Photo of display">[details]</a></span>). In
my theory this is caused by the two DisplayPort outputs not being in sync - the
screen needs both tiles to be in sync (i.e. scanlines to match) to make a
composite final image.
The Dell UP2715K monitor has two DP 1.2 inputs, two tiles expecting
2560x2880@60Hz modes (as exposed in EDID/DisplayInfo data). Connected to Radeon
Pro WX2100 (Polaris 12).
This used to be actually working reliably in kernel 4.20.0, yesterday I fired
up kernel 5.1.1 and only got garbage on my screen. Also tested drm-tip kernel
that includes drm-next-5.2 branch from the agd5f repo
(<a href="https://patchwork.freedesktop.org/patch/304430/">https://patchwork.freedesktop.org/patch/304430/</a>) - same issue.
I haven't got time to bisect the change yet, I was hoping you could point me to
a possible commit that broke this. By any chance, do you AMD guys have a 5k
tiled screen inhouse for testing?</pre>
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