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<body><span class="vcard"><a class="email" href="mailto:krh@bitplanet.net" title="Kristian Høgsberg <krh@bitplanet.net>"> <span class="fn">Kristian Høgsberg</span></a>
</span> changed
<a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED NOTABUG - Protocol: wl_buffer.release is racy"
href="https://bugs.freedesktop.org/show_bug.cgi?id=75303">bug 75303</a>
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<table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>What</th>
<th>Removed</th>
<th>Added</th>
</tr>
<tr>
<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>NOTABUG
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<b><a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED NOTABUG - Protocol: wl_buffer.release is racy"
href="https://bugs.freedesktop.org/show_bug.cgi?id=75303#c2">Comment # 2</a>
on <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED NOTABUG - Protocol: wl_buffer.release is racy"
href="https://bugs.freedesktop.org/show_bug.cgi?id=75303">bug 75303</a>
from <span class="vcard"><a class="email" href="mailto:krh@bitplanet.net" title="Kristian Høgsberg <krh@bitplanet.net>"> <span class="fn">Kristian Høgsberg</span></a>
</span></b>
<pre>(In reply to <a href="show_bug.cgi?id=75303#c0">comment #0</a>)
<span class="quote">> Consider a client doing this:
> 1. surface1.attach(buffer1)
> 2. surface1.commit
> 3. surface2.attach(buffer1)
> 4. surface2.commit
>
> Then the client receives buffer1.release.
>
> It is ambiguous, whether the release corresponds to step 2 or step 4. That
> is, the client cannot know if the latter commit still holds the buffer
> reserved in the server. The server may have had time to process and release
> the buffer before step 4, in which case the buffer would be reserved again
> after step 4.
>
> The problem is the same also, if surface1 and surface2 were both just
> surface1. If the compositor has time to repaint in between the commits, the
> client may get a release it most likely interprets as the release
> corresponding to step 4, which would be wrong.
>
> How should this be resolved?
>
> A suggestion from Jason Ekstrand was to modify the protocol to guarantee one
> release event for each commit that makes the buffer reserved. This would
> allow clients to use simple reference counting.</span >
We do that now. Every attach+commit is followed by a release. If a client
attaches a buffer to two surfaces, it needs to receive two release events
before it can use the buffer again without causing artifacts.</pre>
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