glamor: don't do render ops with matching source/dest (v2)

XRender defines this, GL really doesn't like it.

kwin 4.x and qt 4.x seem to make this happen for the
gradient in the titlebar, and on radeonsi/r600 hw
this draws all kinds of wrong.

v2: bump this up a level, and check it earlier.
(I assume the XXXX was for this case.)

[This corresponds to fa12f2c150b2f50de9dac4a2b09265f13af353af in master,
fixed up for 1.17 branch. - ajax]

Signed-off-by: Dave Airlie <airlied@redhat.com>

2 files changed, 18 insertions, 1 deletions

diff --git a/glamor/glamor_largepixmap.c b/glamor/glamor_largepixmap.c
index 9b2458453..b9c3b9af1 100644
--- a/glamor/glamor_largepixmap.c
+++ b/glamor/glamor_largepixmap.c
@@ -1046,6 +1046,15 @@ glamor_composite_largepixmap_region(CARD8 op,
     int source_repeat_type = 0, mask_repeat_type = 0;
     int ok = TRUE;
 
+    if (source_pixmap_priv == dest_pixmap_priv) {
+        glamor_fallback("source and dest pixmaps are the same\n");
+        return FALSE;
+    }
+    if (mask_pixmap_priv ==  dest_pixmap_priv) {
+        glamor_fallback("mask and dest pixmaps are the same\n");
+        return FALSE;
+    }
+
     if (source->repeat)
         source_repeat_type = source->repeatType;
     else
diff --git a/glamor/glamor_render.c b/glamor/glamor_render.c
index 2386f2e2e..d9b16ea05 100644
--- a/glamor/glamor_render.c
+++ b/glamor/glamor_render.c
@@ -1400,6 +1400,7 @@ glamor_composite_clipped_region(CARD8 op,
 {
     ScreenPtr screen = dest->pDrawable->pScreen;
     PixmapPtr source_pixmap = NULL, mask_pixmap = NULL;
+    PixmapPtr dest_pixmap = glamor_get_drawable_pixmap(dest->pDrawable);
     PicturePtr temp_src = source, temp_mask = mask;
     glamor_pixmap_private *temp_src_priv = source_pixmap_priv;
     glamor_pixmap_private *temp_mask_priv = mask_pixmap_priv;
@@ -1502,7 +1503,14 @@ glamor_composite_clipped_region(CARD8 op,
         }
     }
 
-    /*XXXXX, self copy? */
+    if (source_pixmap == dest_pixmap) {
+        glamor_fallback("source and dest pixmaps are the same\n");
+        goto out;
+    }
+    if (mask_pixmap == dest_pixmap) {
+        glamor_fallback("mask and dest pixmaps are the same\n");
+        goto out;
+    }
 
     x_dest += dest->pDrawable->x;
     y_dest += dest->pDrawable->y;