[PATCH xserver 1/3] modesetting: ms_dri2_create_buffer: check screen of existing front buffers

[Hans de Goede]

If a frontbuffer drawable already has a pixmap, make sure it was created
on the right screen.

Signed-off-by: Hans de Goede <hdegoede at redhat.com>
---
 hw/xfree86/drivers/modesetting/dri2.c | 20 +++++++-------------
 1 file changed, 7 insertions(+), 13 deletions(-)

diff --git a/hw/xfree86/drivers/modesetting/dri2.c b/hw/xfree86/drivers/modesetting/dri2.c
index 83cb3e0..b810d59 100644
--- a/hw/xfree86/drivers/modesetting/dri2.c
+++ b/hw/xfree86/drivers/modesetting/dri2.c
@@ -117,17 +117,6 @@ get_drawable_pixmap(DrawablePtr drawable)
         return screen->GetWindowPixmap((WindowPtr) drawable);
 }
 
-static PixmapPtr
-get_front_buffer(DrawablePtr drawable)
-{
-    PixmapPtr pixmap;
-
-    pixmap = get_drawable_pixmap(drawable);
-    pixmap->refcnt++;
-
-    return pixmap;
-}
-
 static DRI2Buffer2Ptr
 ms_dri2_create_buffer(DrawablePtr drawable, unsigned int attachment,
                       unsigned int format)
@@ -151,8 +140,13 @@ ms_dri2_create_buffer(DrawablePtr drawable, unsigned int attachment,
     }
 
     pixmap = NULL;
-    if (attachment == DRI2BufferFrontLeft)
-        pixmap = get_front_buffer(drawable);
+    if (attachment == DRI2BufferFrontLeft) {
+        pixmap = get_drawable_pixmap(drawable);
+        if (pixmap && pixmap->drawable.pScreen != screen)
+            pixmap = NULL;
+        if (pixmap)
+            pixmap->refcnt++;
+    }
 
     if (pixmap == NULL) {
         int pixmap_width = drawable->width;
-- 
2.7.4