loader/dri3: Only wait for back buffer fences in dri3_get_buffer

We don't need to wait before drawing to the fake front buffer, as front
buffer rendering by definition is allowed to produce artifacts.

Fixes hangs in some cases when re-using the fake front buffer, due to it
still being busy (i.e. in use for presentation).

Cc: mesa-stable@lists.freedesktop.org
Bugzilla: https://bugs.freedesktop.org/106404
Bugzilla: https://bugs.freedesktop.org/107757
Tested-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>

diff --git a/src/loader/loader_dri3_helper.c b/src/loader/loader_dri3_helper.c
index b62521485837d5de1467ef5f3314c5398352c145..258678a6662f0bf0dde60e6372ac09364c857bb9 100644 (file)
--- a/src/loader/loader_dri3_helper.c
+++ b/src/loader/loader_dri3_helper.c
@@ -1818,7 +1818,9 @@ dri3_get_buffer(__DRIdrawable *driDrawable,
       buffer = new_buffer;
       draw->buffers[buf_id] = buffer;
    }
-   dri3_fence_await(draw->conn, draw, buffer);
+
+   if (buffer_type == loader_dri3_buffer_back)
+      dri3_fence_await(draw->conn, draw, buffer);
 
    /*
     * Do we need to preserve the content of a previous buffer?