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<body><span class="vcard"><a class="email" href="mailto:chris@chris-wilson.co.uk" title="Chris Wilson <chris@chris-wilson.co.uk>"> <span class="fn">Chris Wilson</span></a>
</span> changed
<a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - [CI][BAT][hsw] igt@i915_selftest@live_blt - incoherency"
href="https://bugs.freedesktop.org/show_bug.cgi?id=112147">bug 112147</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>
</tr>
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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>---
</td>
<td>FIXED
</td>
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<b><a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - [CI][BAT][hsw] igt@i915_selftest@live_blt - incoherency"
href="https://bugs.freedesktop.org/show_bug.cgi?id=112147#c10">Comment # 10</a>
on <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - [CI][BAT][hsw] igt@i915_selftest@live_blt - incoherency"
href="https://bugs.freedesktop.org/show_bug.cgi?id=112147">bug 112147</a>
from <span class="vcard"><a class="email" href="mailto:chris@chris-wilson.co.uk" title="Chris Wilson <chris@chris-wilson.co.uk>"> <span class="fn">Chris Wilson</span></a>
</span></b>
<pre>Just the normal stab in the dark,
commit f9228f7658734fe16ef7eec554d187a3d9577be8 (HEAD -> drm-intel-next-queued,
drm-intel/drm-intel-next-queued)
Author: Chris Wilson <<a href="mailto:chris@chris-wilson.co.uk">chris@chris-wilson.co.uk</a>>
Date: Mon Nov 11 12:09:57 2019 +0000
drm/i915/gt: Try an extra flush on the Haswell blitter
On gen7, including Haswell, the MI_FLUSH_DW command is not synchronous
with the command streamer nor is there an option to make it so. To hide
this we add a large delay on the CS so that the breadcrumb should always
be visible before the interrupt. However, that does not seem to be
enough to ensure the memory is actually coherent with the read of the
breadcrumb. The breadcrumb update is a post-sync op... Throw in a
preliminary MI_FLUSH_DW before the breadcrumb update in the hope that
helps.
References: <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - [CI][BAT][hsw] igt@i915_selftest@live_blt - incoherency"
href="show_bug.cgi?id=112147">https://bugs.freedesktop.org/show_bug.cgi?id=112147</a>
Testcase: igt/i915_selftest/live_blt
Signed-off-by: Chris Wilson <<a href="mailto:chris@chris-wilson.co.uk">chris@chris-wilson.co.uk</a>>
Acked-by: Mika Kuoppala <<a href="mailto:mika.kuoppala@linux.intel.com">mika.kuoppala@linux.intel.com</a>>
Link:
<a href="https://patchwork.freedesktop.org/patch/msgid/20191111120957.17732-1-chris@chris-wilson.co.uk">https://patchwork.freedesktop.org/patch/msgid/20191111120957.17732-1-chris@chris-wilson.co.uk</a></pre>
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