From aeeae1b40fc012bcc01fcd2243d4993de819b7cf Mon Sep 17 00:00:00 2001
From: Eric Anholt <eric@anholt.net>
Date: Mon, 26 Feb 2007 09:13:17 -0800
Subject: [PATCH] Fix a crash in startup monitor detect.

---
 src/i830_display.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/i830_display.c b/src/i830_display.c
index f3beb572..a1660e35 100644
--- a/src/i830_display.c
+++ b/src/i830_display.c
@@ -342,7 +342,13 @@ i830PipeSetBase(xf86CrtcPtr crtc, int x, int y)
     int dspbase = (pipe == 0 ? DSPABASE : DSPBBASE);
     int dspsurf = (pipe == 0 ? DSPASURF : DSPBSURF);
 
-    if (crtc->rotatedData != NULL) {
+    if (pI830->front_buffer == NULL) {
+	/* During startup we may be called as part of monitor detection while
+	 * there is no memory allocation done, so just supply a dummy base
+	 * address.
+	 */
+	Start = 0;
+    } else if (crtc->rotatedData != NULL) {
 	Start = (char *)crtc->rotatedData - (char *)pI830->FbBase;
     } else if (I830IsPrimary(pScrn)) {
 	Start = pI830->front_buffer->offset;