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      <base href="https://bugs.freedesktop.org/" />
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    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - Attempt to use kde/plasma renders the system immediately unresponsive"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=94694">94694</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Attempt to use kde/plasma renders the system immediately unresponsive
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>Mesa
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>11.1
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>x86-64 (AMD64)
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>Linux (All)
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>major
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>medium
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>Drivers/DRI/nouveau
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>nouveau@lists.freedesktop.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>oakad@yahoo.com
          </td>
        </tr>

        <tr>
          <th>QA Contact</th>
          <td>nouveau@lists.freedesktop.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Created <span class=""><a href="attachment.cgi?id=122538" name="attach_122538" title="Xorg.0.log for the failed session">attachment 122538</a> <a href="attachment.cgi?id=122538&action=edit" title="Xorg.0.log for the failed session">[details]</a></span>
Xorg.0.log for the failed session

The crux of the problem: 

Mar 25 23:40:25 mercador kernel: nouveau 0000:01:00.0: plasmashell[6208]:
failed
 to idle channel 17 [plasmashell[6208]]
Mar 25 23:40:27 mercador kernel: nouveau 0000:01:00.0: timeout at
drivers/gpu/dr
m/nouveau/nvkm/engine/fifo/gpfifogf100.c:66/gf100_fifo_gpfifo_engine_fini()!
Mar 25 23:40:27 mercador kernel: nouveau 0000:01:00.0: fifo: channel 17
[plasmas
hell[6208]] kick timeout
Mar 25 23:40:27 mercador kernel: nouveau: plasmashell[6208]:00000000:0000906f:
d
etach gr failed, -16
Mar 25 23:40:27 mercador kernel: nouveau 0000:01:00.0: fifo: SCHED_ERROR 0d []
Mar 25 23:40:29 mercador kernel: nouveau 0000:01:00.0: timeout at
drivers/gpu/dr
m/nouveau/nvkm/engine/fifo/gpfifogf100.c:66/gf100_fifo_gpfifo_engine_fini()!
Mar 25 23:40:29 mercador kernel: nouveau 0000:01:00.0: fifo: channel 17
[plasmas
hell[6208]] kick timeout
Mar 25 23:40:29 mercador kernel: nouveau: plasmashell[6208]:00000000:0000906f:
d
etach sw failed, -16
Mar 25 23:40:44 mercador kernel: nouveau 0000:01:00.0: plasmashell[6208]:
failed
 to idle channel 17 [plasmashell[6208]]

This will happen immediately upon any interaction with KDE 5 panel.

At this moment system is rendered inoperable, even though it may still possible
to reboot it over network. The CPU usage becomes high, apparently being
consumed by an in-kernel thread.

The kernel version is 4.4.6
Kde/plasma version is 5.19.0, qt is 5.5.1
X11/nouveau driver version is 1.0.12

Xorg.0.log is attached (with some additional errors signalling that event queue
is filling up).</pre>
        </div>
      </p>
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