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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]gem_mmap_gtt/coherency failing assertion cpu[x] == i"
href="https://bugs.freedesktop.org/show_bug.cgi?id=100587">bug 100587</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;">Resolution</td>
<td>WONTFIX
</td>
<td>FIXED
</td>
</tr>
<tr>
<td style="text-align:right;">Status</td>
<td>CLOSED
</td>
<td>RESOLVED
</td>
</tr></table>
<p>
<div>
<b><a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - [CI]gem_mmap_gtt/coherency failing assertion cpu[x] == i"
href="https://bugs.freedesktop.org/show_bug.cgi?id=100587#c26">Comment # 26</a>
on <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - [CI]gem_mmap_gtt/coherency failing assertion cpu[x] == i"
href="https://bugs.freedesktop.org/show_bug.cgi?id=100587">bug 100587</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>kernel commit 900ccf30f9e112b508a61b228bf014e3bea14bc4 (HEAD ->
drm-intel-next-queued, drm-intel/for-linux-next,
drm-intel/drm-intel-next-queued)
Author: Chris Wilson <<a href="mailto:chris@chris-wilson.co.uk">chris@chris-wilson.co.uk</a>>
Date: Fri Jul 20 11:19:10 2018 +0100
drm/i915: Only force GGTT coherency w/a on required chipsets
Not all chipsets have an internal buffer delaying the visibility of
writes via the GGTT being visible by other physical paths, but we use a
very heavy workaround for all. We only need to apply that workarounds to
the chipsets we know suffer from the delay and the resulting coherency
issue.
Similarly, the same inconsistent coherency fouls up our ABI promise that
a write into a mmap_gtt is immediately visible to others. Since the HW
has made that a lie, let userspace know when that contract is broken.
(Not that userspace would want to use mmap_gtt on those chipsets for
other performance reasons...)
Testcase: igt/drv_selftest/live_coherency
Testcase: igt/gem_mmap_gtt/coherency
Bugzilla: <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - [CI]gem_mmap_gtt/coherency failing assertion cpu[x] == i"
href="show_bug.cgi?id=100587">https://bugs.freedesktop.org/show_bug.cgi?id=100587</a>
Signed-off-by: Chris Wilson <<a href="mailto:chris@chris-wilson.co.uk">chris@chris-wilson.co.uk</a>>
Cc: Joonas Lahtinen <<a href="mailto:joonas.lahtinen@linux.intel.com">joonas.lahtinen@linux.intel.com</a>>
Reviewed-by: Tomasz Lis <<a href="mailto:tomasz.lis@intel.com">tomasz.lis@intel.com</a>>
Reviewed-by: Tvrtko Ursulin <<a href="mailto:tvrtko.ursulin@intel.com">tvrtko.ursulin@intel.com</a>>
Link:
<a href="https://patchwork.freedesktop.org/patch/msgid/20180720101910.11153-1-chris@chris-wilson.co.uk">https://patchwork.freedesktop.org/patch/msgid/20180720101910.11153-1-chris@chris-wilson.co.uk</a>
igt commit 65cdccdc7bcbb791d791aeeeecb784a382110a3c (HEAD, upstream/master)
Author: Chris Wilson <<a href="mailto:chris@chris-wilson.co.uk">chris@chris-wilson.co.uk</a>>
Date: Fri Jul 20 09:02:26 2018 +0100
igt/gem_mmap_gtt: Check for known incoherency before testing
We test map_gtt coherency (whether or not a write via the mmap_gtt is
immediately visible in the backing storage to a read via mmap_cpu) but
we know that several platforms are inherently incorrect and require some
form of hammer to workaround internal delays. These platforms break our
ABI guarantees and so we report the change in ABI via a driver getparam.
If we know the platform doesn't meet the ABI guarantee, skip the test.
If it is meant to work, test!
Bugzilla: <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - [CI]gem_mmap_gtt/coherency failing assertion cpu[x] == i"
href="show_bug.cgi?id=100587">https://bugs.freedesktop.org/show_bug.cgi?id=100587</a>
Signed-off-by: Chris Wilson <<a href="mailto:chris@chris-wilson.co.uk">chris@chris-wilson.co.uk</a>>
Cc: Joonas Lahtinen <<a href="mailto:joonas.lahtinen@linux.intel.com">joonas.lahtinen@linux.intel.com</a>>
Reviewed-by: Tvrtko Ursulin <<a href="mailto:tvrtko.ursulin@intel.com">tvrtko.ursulin@intel.com</a>></pre>
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