exa: avoid calling non existent SourceValidate callback

In unaccel path we were unconditionaly calling the SourceValidate
callback but in some case it could be NULL. Check if we have a
valid callback before calling it.

Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Acked-by: Michel Dänzer <michel@daenzer.net>
Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/exa/exa_unaccel.c b/exa/exa_unaccel.c
index db9ce9f56..8159f2f26 100644
--- a/exa/exa_unaccel.c
+++ b/exa/exa_unaccel.c
@@ -462,9 +462,11 @@ ExaSrcValidate(DrawablePtr pDrawable,
     REGION_UNION(pScreen, dst, dst, &reg);
     REGION_UNINIT(pScreen, &reg);
 
-    swap(pExaScr, pScreen, SourceValidate);
-    pScreen->SourceValidate(pDrawable, x, y, width, height);
-    swap(pExaScr, pScreen, SourceValidate);
+    if (pScreen->SourceValidate) {
+        swap(pExaScr, pScreen, SourceValidate);
+        pScreen->SourceValidate(pDrawable, x, y, width, height);
+        swap(pExaScr, pScreen, SourceValidate);
+    }
 }
 
 static Bool