st/dri: fix crash with HUD and single buffering

diff --git a/src/gallium/state_trackers/dri/common/dri_drawable.c b/src/gallium/state_trackers/dri/common/dri_drawable.c
index 00ae1da..cd4a36a 100644 (file)
--- a/src/gallium/state_trackers/dri/common/dri_drawable.c
+++ b/src/gallium/state_trackers/dri/common/dri_drawable.c
@@ -435,7 +435,8 @@ dri_flush(__DRIcontext *cPriv,
    }
 
    /* Flush the drawable. */
-   if (flags & __DRI2_FLUSH_DRAWABLE) {
+   if ((flags & __DRI2_FLUSH_DRAWABLE) &&
+       drawable->textures[ST_ATTACHMENT_BACK_LEFT]) {
       /* Resolve MSAA buffers. */
       if (drawable->stvis.samples > 1) {
          dri_msaa_resolve(ctx, drawable, ST_ATTACHMENT_BACK_LEFT);