xlib/shm: Limit use of the impromptu fallback pixmap for uploads

We want to avoid unnecessary readback and so only want to use the
ShmPixmap when uploading the complete surface.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 2 insertions, 1 deletions

diff --git a/src/cairo-xlib-private.h b/src/cairo-xlib-private.h
index 8e9c044db..b704c6b28 100644
--- a/src/cairo-xlib-private.h
+++ b/src/cairo-xlib-private.h
@@ -404,7 +404,8 @@ _cairo_xlib_surface_create_similar_shm (void *surface,
 					int width, int height);
 
 cairo_private cairo_surface_t *
-_cairo_xlib_surface_get_shm (cairo_xlib_surface_t *surface);
+_cairo_xlib_surface_get_shm (cairo_xlib_surface_t *surface,
+			     cairo_bool_t overwrite);
 
 cairo_private cairo_int_status_t
 _cairo_xlib_surface_put_shm (cairo_xlib_surface_t *surface);