1 files changed, 16 insertions, 0 deletions
diff --git a/src/i830_uxa.c b/src/i830_uxa.c
index eb35014e..ef7ac84a 100644
--- a/src/i830_uxa.c
+++ b/src/i830_uxa.c
@@ -627,6 +627,22 @@ i830_uxa_create_pixmap (ScreenPtr screen, int w, int h, int depth, unsigned usag
 	     * with drm_intel_bufmgr_check_aperture().
 	     */
 	    size = i830_get_fence_size(i830, stride * h);
+	    assert(size >= stride * h);
+	}
+
+	/* Fail very large allocations on 32-bit systems.  Large BOs will
+	 * tend to hit SW fallbacks frequently, and also will tend to fail
+	 * to successfully map when doing SW fallbacks because we overcommit
+	 * address space for BO access.
+	 *
+	 * Note that size should fit in 32 bits.  We throw out >32767x32767x4,
+	 * and pitch alignment could get us up to 32768x32767x4.
+	 */
+	if (sizeof(unsigned int) == 4 &&
+	    size > (unsigned int)(1024 * 1024 * 1024))
+	{
+	    fbDestroyPixmap (pixmap);
+	    return NullPixmap;
 	}
 
 	bo = drm_intel_bo_alloc_for_render(i830->bufmgr, "pixmap", size, 0);