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<base href="https://bugs.freedesktop.org/" />
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<th>Priority</th>
<td>medium
</td>
</tr>
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - [BYT]Sysfs RC6 residency counter is inaccurate"
href="https://bugs.freedesktop.org/show_bug.cgi?id=76877">76877</a>
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<th>CC</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
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<th>Assignee</th>
<td>intel-gfx-bugs@lists.freedesktop.org
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</tr>
<tr>
<th>Summary</th>
<td>[BYT]Sysfs RC6 residency counter is inaccurate
</td>
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<th>QA Contact</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Classification</th>
<td>Unclassified
</td>
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<th>OS</th>
<td>All
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<th>Reporter</th>
<td>wendy.wang@intel.com
</td>
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<th>Hardware</th>
<td>Other
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</td>
</tr>
<tr>
<th>Component</th>
<td>DRM/Intel
</td>
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<th>Product</th>
<td>DRI
</td>
</tr></table>
<p>
<div>
<pre>Test on BYT with kernel: 3.14.0-rc8_drm-intel-nightly_19f629_20140331+
Run below script:
BEFORE=`cat /sys/class/drm/card0/power/rc6_residency_ms`
time sleep 10
AFTER=`cat /sys/class/drm/card0/power/rc6_residency_ms`
echo BEFORE = $BEFORE
echo AFTER = $AFTER
DELTA=$((AFTER - BEFORE))
echo DELTA = $DELTA
echo "scale=2; ($DELTA / 1000) / 10" | bc -l
Show the result:
real 0m10.002s
user 0m0.000s
sys 0m0.002s
BEFORE = 1281484
AFTER = 1292928
DELTA = 11444
1.14
So there should be something is wrong with Sysfs RC6 residency counter on BYT.
Cannot reproduce this issue on HSW and IVB platform.</pre>
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