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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 - intelReadPixels: fallback to CPU mapping in PBO case for Z24S8 attachments"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=106800">106800</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>intelReadPixels: fallback to CPU mapping in PBO case for Z24S8 attachments
          </td>
        </tr>

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

        <tr>
          <th>Version</th>
          <td>git
          </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>Drivers/DRI/i965
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>intel-3d-bugs@lists.freedesktop.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>wickmarkus@web.de
          </td>
        </tr>

        <tr>
          <th>QA Contact</th>
          <td>intel-3d-bugs@lists.freedesktop.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Created <span class=""><a href="attachment.cgi?id=139997" name="attach_139997" title="Apitrace dump of citra showing the performance issue">attachment 139997</a> <a href="attachment.cgi?id=139997&action=edit" title="Apitrace dump of citra showing the performance issue">[details]</a></span>
Apitrace dump of citra showing the performance issue

Hi,

calling glReadPixels for the GL_DEPTH24_STENCIL8 attachment and the
GL_DEPTH_STENCIL / GL_UNSIGNED_INT_24_8 format seems to stall the GPU, even if
a PBO is bound. 92% of my CPU time is spend in intel_miptree_map.

I guess i965 lacks a copy shader for the tiled Z24S8 attachment to the linear
TBO buffer.

Tests was done on: Mesa DRI Intel(R) UHD Graphics 620 (Kabylake GT2)
and mesa: 4affeba1e9eb426a1ba13a3e8ced4673c4bb9b34

An apitrace dump which highlights this issue in the last frames is attached.</pre>
        </div>
      </p>


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