From 89c3dfe41e3a17a4f27b20e23623dc5777670feb Mon Sep 17 00:00:00 2001
From: Dave Airlie <airlied@redhat.com>
Date: Thu, 29 Nov 2007 19:57:24 +1100
Subject: [PATCH] modes: use xf86RandR12Index to stop illegal access

xf86RandR12Index set to -1, and if initialised it gets 0 or higher.
This allows the server to start with xinerama turned on with only one head
---
 hw/xfree86/modes/xf86RandR12.c | 30 ++++++++++++++++++------------
 1 file changed, 18 insertions(+), 12 deletions(-)

diff --git a/hw/xfree86/modes/xf86RandR12.c b/hw/xfree86/modes/xf86RandR12.c
index 8fbb877b1..bb7f94581 100644
--- a/hw/xfree86/modes/xf86RandR12.c
+++ b/hw/xfree86/modes/xf86RandR12.c
@@ -59,7 +59,7 @@ static Bool xf86RandR12Init12 (ScreenPtr pScreen);
 static Bool xf86RandR12CreateScreenResources12 (ScreenPtr pScreen);
 #endif
 
-static int	    xf86RandR12Index;
+static int	    xf86RandR12Index = -1;
 static int	    xf86RandR12Generation;
 
 #define XF86RANDRINFO(p) \
@@ -340,10 +340,12 @@ xf86RandR12ScreenSetSize (ScreenPtr	pScreen,
     PixmapPtr		pScrnPix = (*pScreen->GetScreenPixmap)(pScreen);
     Bool		ret = FALSE;
 
-    if (randrp->virtualX == -1 || randrp->virtualY == -1)
-    {
-	randrp->virtualX = pScrn->virtualX;
-	randrp->virtualY = pScrn->virtualY;
+    if (xf86RandR12Index != -1) {
+        if (randrp->virtualX == -1 || randrp->virtualY == -1)
+        {
+	    randrp->virtualX = pScrn->virtualX;
+	    randrp->virtualY = pScrn->virtualY;
+        }
     }
     if (pRoot && pScrn->vtSema)
 	(*pScrn->EnableDisableFBAccess) (pScreen->myNum, FALSE);
@@ -366,7 +368,7 @@ finish:
     if (pRoot && pScrn->vtSema)
 	(*pScrn->EnableDisableFBAccess) (pScreen->myNum, TRUE);
 #if RANDR_12_INTERFACE
-    if (WindowTable[pScreen->myNum] && ret)
+    if ((xf86RandR12Index != -1) && WindowTable[pScreen->myNum] && ret)
 	RRScreenSizeNotify (pScreen);
 #endif
     return ret;
@@ -466,6 +468,9 @@ xf86RandR12CreateScreenResources (ScreenPtr pScreen)
 				  mmHeight);
     }
 
+    if (xf86RandR12Index == -1)
+	return TRUE;
+
     if (randrp->virtualX == -1 || randrp->virtualY == -1)
     {
 	randrp->virtualX = pScrn->virtualX;
@@ -533,15 +538,17 @@ xf86RandR12Init (ScreenPtr pScreen)
 _X_EXPORT void
 xf86RandR12SetRotations (ScreenPtr pScreen, Rotation rotations)
 {
-    XF86RandRInfoPtr	randrp = XF86RANDRINFO(pScreen);
+    XF86RandRInfoPtr	randrp;
 #if RANDR_12_INTERFACE
     ScrnInfoPtr		pScrn = xf86Screens[pScreen->myNum];
     int			c;
     xf86CrtcConfigPtr   config = XF86_CRTC_CONFIG_PTR(pScrn);
 #endif
-    if (!xf86RandR12Index)
+
+    if (xf86RandR12Index == -1)
 	return;
 
+    randrp = XF86RANDRINFO(pScreen);
 #if RANDR_12_INTERFACE
     for (c = 0; c < config->num_crtc; c++) {
 	xf86CrtcPtr    crtc = config->crtc[c];
@@ -1066,11 +1073,10 @@ static Bool
 xf86RandR12CreateScreenResources12 (ScreenPtr pScreen)
 {
     int			c;
-    XF86RandRInfoPtr	randrp = XF86RANDRINFO(pScreen);
     ScrnInfoPtr		pScrn = xf86Screens[pScreen->myNum];
     xf86CrtcConfigPtr   config = XF86_CRTC_CONFIG_PTR(pScrn);
 
-    if (!xf86RandR12Index)
+    if (xf86RandR12Index == -1)
 	return TRUE;
 
     for (c = 0; c < config->num_crtc; c++)
@@ -1091,11 +1097,11 @@ xf86RandR12TellChanged (ScreenPtr pScreen)
 {
     ScrnInfoPtr		pScrn = xf86Screens[pScreen->myNum];
     xf86CrtcConfigPtr   config = XF86_CRTC_CONFIG_PTR(pScrn);
-    XF86RandRInfoPtr	randrp = XF86RANDRINFO(pScreen);
     int			c;
 
-    if (!xf86RandR12Index)
+    if (xf86RandR12Index == -1)
 	return;
+
     xf86RandR12SetInfo12 (pScreen);
     for (c = 0; c < config->num_crtc; c++)
 	xf86RandR12CrtcNotify (config->crtc[c]->randr_crtc);