[PATCH 1/2] DRI2: Avoid call to NULL pointer

[Pauli Nieminen]

DDX driver may implement schedule swap without GetMSC. In that case we
can't call GetMSC in DRI2SwapBuffers.

Signed-off-by: Pauli Nieminen <ext-pauli.nieminen at nokia.com>
Reviewed-by: Mario Kleiner <mario.kleiner at tuebingen.mpg.de>
CC: Keith Packard <keithp at keithp.com>
CC: Kristian Høgsberg <krh at bitplanet.net>
---
 hw/xfree86/dri2/dri2.c |   11 +++++++----
 1 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/hw/xfree86/dri2/dri2.c b/hw/xfree86/dri2/dri2.c
index 228c0e0..d9b9d57 100644
--- a/hw/xfree86/dri2/dri2.c
+++ b/hw/xfree86/dri2/dri2.c
@@ -856,11 +856,14 @@ DRI2SwapBuffers(ClientPtr client, DrawablePtr pDraw, CARD64 target_msc,
 	 * is moved to a crtc with a lower refresh rate, or a crtc that just
 	 * got enabled.
 	 */
-	if (!(*ds->GetMSC)(pDraw, &ust, &current_msc))
-	    pPriv->last_swap_target = 0;
+	if (ds->GetMSC) {
+	    if (!(*ds->GetMSC)(pDraw, &ust, &current_msc))
+		pPriv->last_swap_target = 0;
 
-	if (current_msc < pPriv->last_swap_target)
-	    pPriv->last_swap_target = current_msc;
+	    if (current_msc < pPriv->last_swap_target)
+		pPriv->last_swap_target = current_msc;
+
+	}
 
 	/*
 	 * Swap target for this swap is last swap target + swap interval since
-- 
1.7.0.4