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<body><span class="vcard"><a class="email" href="mailto:amonakov@gmail.com" title="Alexander Monakov <amonakov@gmail.com>"> <span class="fn">Alexander Monakov</span></a>
</span> changed
<a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED NOTOURBUG - [SNA] Garbage in window after filling backbuffer with glDrawPixels on Mesa-10.1"
href="https://bugs.freedesktop.org/show_bug.cgi?id=77368">bug 77368</a>
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<table border="1" cellspacing="0" cellpadding="8">
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<th>What</th>
<th>Removed</th>
<th>Added</th>
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<td style="text-align:right;">Status</td>
<td>NEW
</td>
<td>RESOLVED
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<td style="text-align:right;">Resolution</td>
<td>---
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<td>NOTOURBUG
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<b><a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED NOTOURBUG - [SNA] Garbage in window after filling backbuffer with glDrawPixels on Mesa-10.1"
href="https://bugs.freedesktop.org/show_bug.cgi?id=77368#c7">Comment # 7</a>
on <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED NOTOURBUG - [SNA] Garbage in window after filling backbuffer with glDrawPixels on Mesa-10.1"
href="https://bugs.freedesktop.org/show_bug.cgi?id=77368">bug 77368</a>
from <span class="vcard"><a class="email" href="mailto:amonakov@gmail.com" title="Alexander Monakov <amonakov@gmail.com>"> <span class="fn">Alexander Monakov</span></a>
</span></b>
<pre>OK. So bisect blames an innocent commit for two reasons:
1. Xorg-1.15 does not have this fix yet:
<a href="http://cgit.freedesktop.org/xorg/xserver/commit/glx?id=96a28e9c914d7ae9b269f73a27b99cbd3c465ac8">http://cgit.freedesktop.org/xorg/xserver/commit/glx?id=96a28e9c914d7ae9b269f73a27b99cbd3c465ac8</a>
(the usual question applies: how could things possibly work before?)
2. PREFER_SMALLER in fbconfig_compare assumes limited range, and does not sort
random visualSelectGroups properly (it says -1000000000 is "more than"
2000000000 due to overflow). So when the bisected-to commit reduces the number
of configs passed to qsort, the order becomes different even if Xserver returns
the same bogus visualSelectGroups.
Hacking around the xorg bug in mesa by clamping selectgroups to 0 fixes the
test for me. And also explains why people were seeing lower performance with
new stack. Next Xorg releases should fix it for real.
So the only thing left on the table is i965-blit-glDrawPixels not working with
MSAA. I'll file that on the Mesa side.</pre>
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