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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 - Flickering and artifacts on dual 4K displays from RX 570"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=109359">109359</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Flickering and artifacts on dual 4K displays from RX 570
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>DRI
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>unspecified
          </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>normal
          </td>
        </tr>

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

        <tr>
          <th>Component</th>
          <td>DRM/AMDgpu
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>venemo@msn.com
          </td>
        </tr></table>
      <p>
        <div>
        <pre>There are two Dell U2718Q 4K monitors connected to a Sapphire Pulse RX 570 ITX
card, one using the DisplayPort output and the other using the HDMI output.

There is a visible flickering artifact on both displays. There is no problem
when only a single display is connected.

Searching online yields a couple of results that suggest a workaround: manually
increasing the shader and/or memory clock of the GPU. On the RX 570 the
following commands can get rid of the problem:

echo "manual" > /sys/class/drm/card0/device/power_dpm_force_performance_level
echo "2" > /sys/class/drm/card0/device/pp_dpm_mclk
echo "5 6 7" > /sys/class/drm/card0/device/pp_dpm_sclk

However, I believe the amdgpu driver should be able to figure out the correct
necessary clock settings on its own. The problem exists in Linux 4.19 and
5.0-rc1 as well.</pre>
        </div>
      </p>


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