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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - rc6_residency_ms unreliable"
href="https://bugs.freedesktop.org/show_bug.cgi?id=94852">94852</a>
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<th>Summary</th>
<td>rc6_residency_ms unreliable
</td>
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<th>Product</th>
<td>DRI
</td>
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<th>Version</th>
<td>unspecified
</td>
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<th>Hardware</th>
<td>Other
</td>
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<th>OS</th>
<td>All
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>medium
</td>
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<th>Component</th>
<td>DRM/Intel
</td>
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<th>Assignee</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
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<th>Reporter</th>
<td>lenb@kernel.org
</td>
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<th>QA Contact</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
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<th>CC</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr></table>
<p>
<div>
<pre>Kernel: Linux-4.6.0-rc1
Hardware: SKL, HSW
Description:
Value read from /sys/class/drm/card0/power/rc6_residency_ms
resets before it reaches 5500 seconds.
This make it "somewhat awkward" to calculate residence from this counter,
since it can effectively go backwards - or worse, appear to increment
extremely slowly when it should really be incrementing quickly.
turbostat has a workaround for former, but there is no workaround
for the later. powertop does not have a workaround, it will just
occasionally display garbage.
Debug steps taken:
booted both the SKL and HSW with cmdline "i915.enable_dc=0"
but it made no difference.
To Reproduce:
while /bin/true; do cat /sys/class/drm/card0/power/rc6_residency_ms; sleep 1;
done
...
5491367
5492352
5493334
5494326
5495307
5496299
5497280
703
1685
2677
3658
4650
5631
6612</pre>
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