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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Low package c-states used only after forcing DPSM to off"
href="https://bugs.freedesktop.org/show_bug.cgi?id=96645">96645</a>
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<th>Summary</th>
<td>Low package c-states used only after forcing DPSM to off
</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>x86-64 (AMD64)
</td>
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<th>OS</th>
<td>Linux (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>
</tr>
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<th>Reporter</th>
<td>gabriele.mzt@gmail.com
</td>
</tr>
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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>I noticed that with v4.7-rc4 the CPU of my laptop can only enter package
c-state 2, while it can normally enter pc7 with v4.6 or older kernels.
I also noticed that after I turned the screen off once running 'xset dpms force
off', the CPU can enter pc7, no matter what's the current state of the display.
I ran a bisection and found that the regression was introduced with commit
ed4a6a7ca853253f9b86f3005d76345482a71283 ("drm/i915: Add two-stage ILK-style
watermark programming (v11)").
My laptop has an i7-4500U CPU and its integrated HD Graphics 4400.
I'm not sure what kind of information are needed to debug the problem, so let
me know what other information I should provide.
Thanks,
Gabriele</pre>
</div>
</p>
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