<html>
<head>
<base href="https://bugs.freedesktop.org/" />
</head>
<body><span class="vcard"><a class="email" href="mailto:przanoni@gmail.com" title="Paulo Zanoni <przanoni@gmail.com>"> <span class="fn">Paulo Zanoni</span></a>
</span> changed
<a class="bz_bug_link
bz_status_ASSIGNED "
title="ASSIGNED - [SNB+ Regression]igt/pm_rpm/universal-planes cause call trace"
href="https://bugs.freedesktop.org/show_bug.cgi?id=89550">bug 89550</a>
<br>
<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>NEEDINFO
</td>
<td>ASSIGNED
</td>
</tr>
<tr>
<td style="text-align:right;">CC</td>
<td>
</td>
<td>matthew.d.roper@intel.com, ville.syrjala@linux.intel.com
</td>
</tr></table>
<p>
<div>
<b><a class="bz_bug_link
bz_status_ASSIGNED "
title="ASSIGNED - [SNB+ Regression]igt/pm_rpm/universal-planes cause call trace"
href="https://bugs.freedesktop.org/show_bug.cgi?id=89550#c5">Comment # 5</a>
on <a class="bz_bug_link
bz_status_ASSIGNED "
title="ASSIGNED - [SNB+ Regression]igt/pm_rpm/universal-planes cause call trace"
href="https://bugs.freedesktop.org/show_bug.cgi?id=89550">bug 89550</a>
from <span class="vcard"><a class="email" href="mailto:przanoni@gmail.com" title="Paulo Zanoni <przanoni@gmail.com>"> <span class="fn">Paulo Zanoni</span></a>
</span></b>
<pre>I did some debugging, here is some relevant information:
At pm_rpm.c:test_one_plane() we set a mode in one monitor, then we set a plane
with drmModeSetPlane(), and then we call
disable_or_dpms_all_screens_and_wait(), which, as the name says, disables all
the modes set. It is this final call that triggers the Kernel WARN.
The problem seems to be that, at __intel_set_mode(), we first call
intel_crtc_disable(), which disables everything, calls drm_vblank_off(), and
also flips intel_crtc->atomic.wait_vblank to true.
Later at __intel_set_mode(), we indirectly call intel_finish_crtc_commit(),
which calls intel_wait_for_vblank() if intel_crtc->atomic.wait_vblank is true.
And we get the WARN because we already disabled vblanks in the previous
paragraph.
So a way to "hide" the WARN would be to just change {ivb,ilk}_disable_plane(),
removing the line that sets intel_crtc->atomic.wait_vblank to true. I didn't
check how to do this on SKL.
That said, Matt or Ville, do you have any comments or insights here?</pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are the QA Contact for the bug.</li>
<li>You are on the CC list for the bug.</li>
<li>You are the assignee for the bug.</li>
</ul>
</body>
</html>