<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 --- - Screen flickering at low resolution when monitor is attached via VGA dongle to DVI port"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=83184">83184</a>
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>dri-devel@lists.freedesktop.org
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Screen flickering at low resolution when monitor is attached via VGA dongle to DVI port
          </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>Rainer.Koenig@ts.fujitsu.com
          </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/Radeon
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>DRI
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Created <span class=""><a href="attachment.cgi?id=105377" name="attach_105377" title="dmesg output with drm debug information">attachment 105377</a> <a href="attachment.cgi?id=105377&action=edit" title="dmesg output with drm debug information">[details]</a></span>
dmesg output with drm debug information

Encountered a strange problem with Radeon HD 6250 (or HD 6310) on a Fujitsu
D3003-S1x mainboard. Occurs with every tested linux distribution and older and
newer kernels. 

Problem occurs only when a monitor is attached via VGA to the DVI port. If the
monitor is attached via DVI then the problem does not occur.

Problem is that
- Monitor is flickering sporadically 
- Monitor resolution is fixed to 1024x768 instead of higher resolutions that
are possible
- xrandr shows 2 monitors while just one monitor is attached

Tried to debug this with kernel parameter drm.debug=14 (dmesg log is attached)
and found the following messages that would explain the flickering screen.

[    4.098364] [drm:radeon_connector_analog_encoder_conflict_solve] 1:
conflicting encoders switching off DVI-I-1
[    4.098369] [drm:radeon_connector_analog_encoder_conflict_solve] in favor of
VGA-1
[    4.219817] [drm:radeon_connector_analog_encoder_conflict_solve] 1:
conflicting encoders switching off VGA-1
[    4.219830] [drm:radeon_connector_analog_encoder_conflict_solve] in favor of
DVI-I-1
[    4.231344] [drm:radeon_connector_analog_encoder_conflict_solve] 1:
conflicting encoders switching off DVI-I-1
[    4.231350] [drm:radeon_connector_analog_encoder_conflict_solve] in favor of
VGA-1
[   13.949336] [drm:radeon_connector_analog_encoder_conflict_solve] 1:
conflicting encoders switching off VGA-1
[   13.949350] [drm:radeon_connector_analog_encoder_conflict_solve] in favor of
DVI-I-1
[   13.967886] [drm:radeon_connector_analog_encoder_conflict_solve] 1:
conflicting encoders switching off DVI-I-1
[   13.967891] [drm:radeon_connector_analog_encoder_conflict_solve] in favor of
VGA-1
[   14.023332] [drm:radeon_connector_analog_encoder_conflict_solve] 1:
conflicting encoders switching off VGA-1
[   14.023345] [drm:radeon_connector_analog_encoder_conflict_solve] in favor of
DVI-I-1
[   14.056688] [drm:radeon_connector_analog_encoder_conflict_solve] 1:
conflicting encoders switching off DVI-I-1
[   14.056694] [drm:radeon_connector_analog_encoder_conflict_solve] in favor of
VGA-1

The problem is still to find the root cause that leads to the issue of having
"conflicting encoders". Any idea what could cause this behaviour?

Regards
Rainer</pre>
        </div>
      </p>
      <hr>
      <span>You are receiving this mail because:</span>
      
      <ul>
          <li>You are the assignee for the bug.</li>
      </ul>
    </body>
</html>