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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] igt@i915_selftest@live_gtt - dmesg-fail - igt_cs_tlb failed with error -22"
href="https://bugs.freedesktop.org/show_bug.cgi?id=111753">bug 111753</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>---
</td>
<td>FIXED
</td>
</tr></table>
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<b><a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - [CI][BAT] igt@i915_selftest@live_gtt - dmesg-fail - igt_cs_tlb failed with error -22"
href="https://bugs.freedesktop.org/show_bug.cgi?id=111753#c2">Comment # 2</a>
on <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - [CI][BAT] igt@i915_selftest@live_gtt - dmesg-fail - igt_cs_tlb failed with error -22"
href="https://bugs.freedesktop.org/show_bug.cgi?id=111753">bug 111753</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>commit c45e788d95b470e9f68fabe1f3cb44beb5dd7840 (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: Thu Sep 19 16:18:11 2019 +0100
drm/i915/tgl: Suspend pre-parser across GTT invalidations
Before we execute a batch, we must first issue any and all TLB
invalidations so that batch picks up the new page table entries.
Tigerlake's preparser is weakening our post-sync CS_STALL inside the
invalidate pipe-control and allowing the loading of the batch buffer
before we have setup its page table (and so it loads the wrong page and
executes indefinitely).
The igt_cs_tlb indicates that this issue can only be observed on rcs,
even though the preparser is common to all engines. Alternatively, we
could do TLB shootdown via mmio on updating the GTT.
By inserting the pre-parser disable inside EMIT_INVALIDATE, we will also
accidentally fixup execution that writes into subsequent batches, such
as gem_exec_whisper and even relocations performed on the GPU. We should
be careful not to allow this disable to become baked into the uABI! The
issue is that if userspace relies on our disabling of the HW
optimisation, when we are ready to enable that optimisation, userspace
will then be broken...
Testcase: igt/i915_selftests/live_gtt/igt_cs_tlb
Bugzilla: <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - [CI][BAT] igt@i915_selftest@live_gtt - dmesg-fail - igt_cs_tlb failed with error -22"
href="show_bug.cgi?id=111753">https://bugs.freedesktop.org/show_bug.cgi?id=111753</a>
Signed-off-by: Chris Wilson <<a href="mailto:chris@chris-wilson.co.uk">chris@chris-wilson.co.uk</a>>
Cc: Daniele Ceraolo Spurio <<a href="mailto:daniele.ceraolospurio@intel.com">daniele.ceraolospurio@intel.com</a>>
Cc: Mika Kuoppala <<a href="mailto:mika.kuoppala@linux.intel.com">mika.kuoppala@linux.intel.com</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/20190919151811.9526-1-chris@chris-wilson.co.uk">https://patchwork.freedesktop.org/patch/msgid/20190919151811.9526-1-chris@chris-wilson.co.uk</a></pre>
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