<html>
    <head>
      <base href="https://bugs.freedesktop.org/">
    </head>
    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - [KBL] Black screen with I915_FORMAT_MOD_Y_TILED_CCS (Requested display configuration exceeds system DDB limitations)"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=111995">111995</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>[KBL] Black screen with I915_FORMAT_MOD_Y_TILED_CCS (Requested display configuration exceeds system DDB limitations)
          </td>
        </tr>

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

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

        <tr>
          <th>Hardware</th>
          <td>Other
          </td>
        </tr>

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

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

        <tr>
          <th>Severity</th>
          <td>not set
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>not set
          </td>
        </tr>

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

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

        <tr>
          <th>Reporter</th>
          <td>contact@emersion.fr
          </td>
        </tr>

        <tr>
          <th>QA Contact</th>
          <td>intel-gfx-bugs@lists.freedesktop.org
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>intel-gfx-bugs@lists.freedesktop.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>This is a bug report for a KBL machine. This issue can be reproduce on both
Sway [1] and Weston. The Sway issue contains a DRM dmesg excerpt.

User-space tries to enable a pipe with a 3840x2160 XRGB8888 buffer. The buffer
is created with gbm_surface_create_with_modifiers. The primary plane supports
I915_FORMAT_MOD_Y_TILED_CCS, it seems like that's what the driver is picking.

However when scanning out the buffer, the driver bails out with "Requested
display configuration exceeds system DDB limitations". This results in a black
screen.

My main question is: both Weston and wlroots except
gbm_surface_create_with_modifiers to pick a modifier so that the buffer can be
scanned out [2]. I wouldn't expect the driver to pick a modifier that doesn't
work.

If this isn't a driver bug, should user-space force LINEAR if the atomic commit
fails? Should it prune the modifier and retry with
gbm_surface_create_with_modifiers?

[1]: <a href="https://github.com/swaywm/wlroots/issues/1852">https://github.com/swaywm/wlroots/issues/1852</a>
[2]:
<a href="https://github.com/swaywm/wlroots/blob/480a31ea4e1a3aadbd053ee2a581cad5d4356876/backend/drm/renderer.c#L87">https://github.com/swaywm/wlroots/blob/480a31ea4e1a3aadbd053ee2a581cad5d4356876/backend/drm/renderer.c#L87</a></pre>
        </div>
      </p>


      <hr>
      <span>You are receiving this mail because:</span>

      <ul>
          <li>You are the QA Contact for the bug.</li>
          <li>You are the assignee for the bug.</li>
          <li>You are on the CC list for the bug.</li>
      </ul>
    </body>
</html>