drm/via: Disable AGP DMA for chips with the new 3D engine.

drivers/char/drm/via_dma.c

@@ -190,6 +190,11 @@ static int via_initialize(drm_device_t * dev,
 		return DRM_ERR(EFAULT);
 	}
 
+	if (dev_priv->chipset == VIA_DX9_0) {
+		DRM_ERROR("AGP DMA is not supported on this chip\n");
+		return DRM_ERR(EINVAL);
+	}
+
 	dev_priv->ring.map.offset = dev->agp->base + init->offset;
 	dev_priv->ring.map.size = init->size;
 	dev_priv->ring.map.type = 0;