<html>
<head>
<base href="https://bugs.freedesktop.org/" />
</head>
<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Priority</th>
<td>medium
</td>
</tr>
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - [i7-4600U i915]: constant screen flickering after KMS which correlates with CPU load"
href="https://bugs.freedesktop.org/show_bug.cgi?id=78162">78162</a>
</td>
</tr>
<tr>
<th>CC</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Assignee</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Summary</th>
<td>[i7-4600U i915]: constant screen flickering after KMS which correlates with CPU load
</td>
</tr>
<tr>
<th>QA Contact</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux (All)
</td>
</tr>
<tr>
<th>Reporter</th>
<td>konush@cern.ch
</td>
</tr>
<tr>
<th>Hardware</th>
<td>x86-64 (AMD64)
</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>
</tr>
<tr>
<th>Product</th>
<td>DRI
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=98309" name="attach_98309" title="example of screen flickering">attachment 98309</a> <a href="attachment.cgi?id=98309&action=edit" title="example of screen flickering">[details]</a></span>
example of screen flickering
Dear developers,
Right after i915 sets native display resolution, boot screen starts to flicker.
Between flickers, text on the screen is sharp, colors are not distorted anyhow.
If there is no CPU activity, this flickering is almost absent, thereas the
amount of screen flickering is proportional to system load. For instance,
command "yes >/dev/null" leads to a lot of flickering (see examples attached).
The very same flickering happens if X is running. In any other aspect my system
runs normally.
The issue seems not to be related to MTRR register setup, but it may be related
to CPU/GPU transitions between various power states.
The system is Thinkpad t440s, i7-4600U, 1920x1080 touchscreen and additional
discrete NVidia GeForce GT 730M graphics card (which was disabled). Tested with
kernel-3.12.18 and kernel-3.15-rc2.</pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are the QA Contact for the bug.</li>
<li>You are on the CC list for the bug.</li>
<li>You are the assignee for the bug.</li>
</ul>
</body>
</html>