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<base href="https://bugs.freedesktop.org/" />
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<th>Priority</th>
<td>medium
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - [945 lvds downclock] Very slow redraw performance"
href="https://bugs.freedesktop.org/show_bug.cgi?id=58843">58843</a>
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<th>Assignee</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
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<th>Summary</th>
<td>[945 lvds downclock] Very slow redraw performance
</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>
</tr>
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<th>OS</th>
<td>All
</td>
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<th>Reporter</th>
<td>lambchop468@gmail.com
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<th>Hardware</th>
<td>x86 (IA32)
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Version</th>
<td>unspecified
</td>
</tr>
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<th>Component</th>
<td>DRM/Intel
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<th>Product</th>
<td>DRI
</td>
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<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=72230" name="attach_72230" title="Patch to manually specify dotclock">attachment 72230</a> <a href="attachment.cgi?id=72230&action=edit" title="Patch to manually specify dotclock">[details]</a></span>
Patch to manually specify dotclock
With LVDS downclock enabled, redraw for some applications slows down a lot.
Symptoms:
urxvt: very slow - I can see each character being drawn onto the screen
glxgears: running with vblank_mode=0, glxgears runs at about 22.5 FPS. If the
window is hidden (I do not use a compositing window manager), glxgears runs at
315 fps or so.
youtube: In Firefox, playing a video with Adobe Flash, and drm.debug=0x2, I can
see that lvds upclock does not happen for frame updates of the video - lvds is
downclocked for continuous periods of time on the order of seconds (expected
behavior?)
openbox: window decorations draw slowly
Everything was fine for kernel 3.4.9. I upgraded today to 3.7.1 and all of
these showed up. I highly suspect [1], combined with reclocking LVDS taking too
long. I can do a bisect upon request.
My panel doesn't actually advertise lower refresh rates through EDID, so I
patched my kernel to let me manually specify a dotclock (patch attached).
I am using SNA. The same symptoms occur on UXA.
Software:
xf86-video-intel: 2.20.5
xserver: 1.12.4
libdrm: 2.4.38
mesa: 8.0.4
kernel: 3.7.1
Hardware:
Acer Aspire One (ZG5/AOA150) - Intel 945GSE
[1]
<a href="http://git.kernel.org/?p=linux/kernel/git/stable/linux-stable.git;a=commitdiff;h=f047e395ddc9da6c307a10629a237502e627ed85;hp=a7b9761d0a2ded58170ffb4d423ff3d7228103f4">http://git.kernel.org/?p=linux/kernel/git/stable/linux-stable.git;a=commitdiff;h=f047e395ddc9da6c307a10629a237502e627ed85;hp=a7b9761d0a2ded58170ffb4d423ff3d7228103f4</a></pre>
</div>
</p>
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