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<body><span class="vcard"><a class="email" href="mailto:mika.kuoppala@intel.com" title="Mika Kuoppala <mika.kuoppala@intel.com>"> <span class="fn">Mika Kuoppala</span></a>
</span> changed
<a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - [CI][BAT] icl incomplete - GEM_BUG_ON(!i915_request_completed(rq)) / GEM_BUG_ON(buf[2 * head + 1] != port->context_id) HSDES#:1806554093"
href="https://bugs.freedesktop.org/show_bug.cgi?id=108315">bug 108315</a>
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<table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>What</th>
<th>Removed</th>
<th>Added</th>
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<td style="text-align:right;">Status</td>
<td>NEW
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<td>RESOLVED
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<td style="text-align:right;">Resolution</td>
<td>---
</td>
<td>FIXED
</td>
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<b><a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - [CI][BAT] icl incomplete - GEM_BUG_ON(!i915_request_completed(rq)) / GEM_BUG_ON(buf[2 * head + 1] != port->context_id) HSDES#:1806554093"
href="https://bugs.freedesktop.org/show_bug.cgi?id=108315#c30">Comment # 30</a>
on <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - [CI][BAT] icl incomplete - GEM_BUG_ON(!i915_request_completed(rq)) / GEM_BUG_ON(buf[2 * head + 1] != port->context_id) HSDES#:1806554093"
href="https://bugs.freedesktop.org/show_bug.cgi?id=108315">bug 108315</a>
from <span class="vcard"><a class="email" href="mailto:mika.kuoppala@intel.com" title="Mika Kuoppala <mika.kuoppala@intel.com>"> <span class="fn">Mika Kuoppala</span></a>
</span></b>
<pre>Optimistically but with a grain of confidence:
commit d8f505311717cfc2033c44a8b26ba96c66187303
Author: Mika Kuoppala <<a href="mailto:mika.kuoppala@linux.intel.com">mika.kuoppala@linux.intel.com</a>>
Date: Wed Dec 5 15:46:12 2018 +0200
drm/i915/icl: Forcibly evict stale csb entries
Gen11 fails to deliver wrt global observation point on
tail/entry updates and we sometimes see old entry.
Use clflush to forcibly evict our possibly stale copy
of the cacheline in hopes that we get fresh one from gpu.
Obviously there is something amiss in the coherency protocol so
this can be consired as a workaround until real cause
is found.
The working hardware will do the evict without our cue anyways,
so the cost in there should be ameliorated by that fact.
v2: for next pass, s/flush/evict, add reset (Chris)
References: <a href="https://bugzilla.freedesktop.org/show_bug.cgi?id=108315">https://bugzilla.freedesktop.org/show_bug.cgi?id=108315</a>
Cc: Chris Wilson <<a href="mailto:chris@chris-wilson.co.uk">chris@chris-wilson.co.uk</a>>
Signed-off-by: Mika Kuoppala <<a href="mailto:mika.kuoppala@linux.intel.com">mika.kuoppala@linux.intel.com</a>>
Reviewed-by: Chris Wilson <<a href="mailto:chris@chris-wilson.co.uk">chris@chris-wilson.co.uk</a>>
Link:
<a href="https://patchwork.freedesktop.org/patch/msgid/20181205134612.24822-1-mika.kuoppala@linux.intel.com">https://patchwork.freedesktop.org/patch/msgid/20181205134612.24822-1-mika.kuoppala@linux.intel.com</a></pre>
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