<html>
<head>
<base href="https://bugs.freedesktop.org/">
</head>
<body>
<p>
<div>
<b><a class="bz_bug_link
bz_status_NEW "
title="NEW - [CI][DRMTIP] igt@kms_rotation_crc@*| igt@kms_chv_cursor_fail@pipe - dmesg-warn - *ERROR* Overflow of CRC buffer, userspace reads too slow."
href="https://bugs.freedesktop.org/show_bug.cgi?id=105127#c4">Comment # 4</a>
on <a class="bz_bug_link
bz_status_NEW "
title="NEW - [CI][DRMTIP] igt@kms_rotation_crc@*| igt@kms_chv_cursor_fail@pipe - dmesg-warn - *ERROR* Overflow of CRC buffer, userspace reads too slow."
href="https://bugs.freedesktop.org/show_bug.cgi?id=105127">bug 105127</a>
from <span class="vcard"><a class="email" href="mailto:matthew.d.roper@intel.com" title="Matt Roper <matthew.d.roper@intel.com>"> <span class="fn">Matt Roper</span></a>
</span></b>
<pre>kms_rotation_crc and kms_cursor_edge_walk (the new name for
kms_chv_cursor_fail) use igt_pipe_crc_start/stop to turn CRC collection on and
off. Between these two calls, an internal buffer of 128 entries will capture
CRC's for each frame and, if the buffer fills up and overflows, the message
here will be reported.
For kms_rotation_crc at least, the manual use of start/stop is unnecessary
since the test is only interested in reading single CRC's at various times and
doesn't care about sequences of frame-by-frame CRC's. Thus switching it over
to the igt_pipe_crc_collect_crc() which will start/stop the CRC collection
around the reading of a single CRC value should solve the problem since the
test won't be collecting a bunch of unwanted CRC values while it's busy doing
other work. I've submitted a patch for that here:
<a href="https://patchwork.freedesktop.org/series/66448/">https://patchwork.freedesktop.org/series/66448/</a>
>From a quick glance, kms_cursor_edge_walk looks like it probably does need a
continuous sequence of CRC values; it may just be that it's doing too long a
sequence of operations between start/stop. I'll look more into the details of
that test later.
Ultimately this defect should have no end-user impact since end user software
doesn't utilize display CRC's. The main impact here is to our CI system, which
will trip over these messages.</pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are on the CC list for the bug.</li>
<li>You are the assignee for the bug.</li>
<li>You are the QA Contact for the bug.</li>
</ul>
</body>
</html>