--- ./drm/shared-core/radeon_irq.c.old	2009-05-12 07:32:27.000000000 +0200
+++ ./drm/shared-core/radeon_irq.c	2009-05-12 07:33:21.000000000 +0200
@@ -295,6 +295,9 @@
 		return -EINVAL;
 	}
 
+   if (!dev_priv->mmio)
+        return -EINVAL;
+
 	if ((dev_priv->flags & RADEON_FAMILY_MASK) >= CHIP_RS690) {
 		if (crtc == 0)
 			return RADEON_READ(R500_D1CRTC_FRAME_COUNT);