disable vga plane before doing CRT hotplug
---
 src/i830_crt.c     |   34 ++++++++++++++++++++++++++++++++++
 src/i830_display.c |   13 +++++++------
 2 files changed, 41 insertions(+), 6 deletions(-)

Index: xf86_video_intel/src/i830_crt.c
===================================================================
--- xf86_video_intel.orig/src/i830_crt.c	2009-08-31 13:10:19.000000000 +0800
+++ xf86_video_intel/src/i830_crt.c	2009-09-18 13:16:21.000000000 +0800
@@ -33,6 +33,7 @@
 #include "i830.h"
 #include "xf86Modes.h"
 #include "i830_display.h"
+#include <unistd.h>
 
 static void
 i830_crt_dpms(xf86OutputPtr output, int mode)
@@ -156,6 +157,38 @@
 
     OUTREG(ADPA, adpa);
 }
+#define VGA_CENTER_MODE		(3 << 24)
+static void
+disable_vga_plane (xf86OutputPtr output)
+{
+    ScrnInfoPtr pScrn = output->scrn;
+    I830Ptr pI830 = I830PTR(pScrn);
+    uint8_t sr01;
+    uint32_t vgadisable;
+
+    vgadisable = INREG(VGACNTRL);
+
+	vgadisable &= ~(VGA_DISP_DISABLE | VGA_CENTER_MODE | VGA_2X_MODE);
+    /*
+     * Bug #17235: G4X machine needs following steps
+     * for disable VGA.
+     * - set bit 5 of SR01;
+     * - Wait 30us;
+     * - disable vga plane;
+     * - restore SR01;
+     */
+	OUTREG8(SRX, 1);
+	sr01 = INREG8(SRX + 1);
+	OUTREG8(SRX + 1, sr01 | (1 << 5));
+	usleep(300);
+
+    OUTREG(VGACNTRL, vgadisable);
+    i830WaitForVblank(pScrn);
+
+	OUTREG8(SRX, 1);
+	OUTREG8(SRX + 1, sr01);
+}
+
 
 /**
  * Uses CRT_HOTPLUG_EN and CRT_HOTPLUG_STAT to detect CRT presence.
@@ -176,6 +209,7 @@
     int		tries = 1;
     int		try;
 
+	disable_vga_plane(output);
     /* On 4 series desktop, CRT detect sequence need to be done twice
      * to get a reliable result. */
     if (IS_G4X(pI830) && !IS_GM45(pI830))
Index: xf86_video_intel/src/i830_display.c
===================================================================
--- xf86_video_intel.orig/src/i830_display.c	2009-09-15 08:53:06.000000000 +0800
+++ xf86_video_intel/src/i830_display.c	2009-09-18 13:14:36.000000000 +0800
@@ -1070,14 +1070,16 @@
     return;
 }
 #endif /* DRM_IOCTL_MODESET_CTL */
-
+#define VGA_CENTER_MODE 	(3 << 24)
 static void
 i830_disable_vga_plane (xf86CrtcPtr crtc)
 {
     ScrnInfoPtr pScrn = crtc->scrn;
     I830Ptr pI830 = I830PTR(pScrn);
     uint8_t sr01;
+    uint32_t vgadisable;
 
+	vgadisable = INREG(VGACNTRL);
     /*
      * Bug #17235: G4X machine needs following steps
      * for disable VGA.
@@ -1086,18 +1088,17 @@
      * - disable vga plane;
      * - restore SR01;
      */
-    if (IS_G4X(pI830)) {
-	OUTREG8(SRX, 1);
+	vgadisable &= ~(VGA_DISP_DISABLE | VGA_2X_MODE | VGA_CENTER_MODE);
+    {	OUTREG8(SRX, 1);
 	sr01 = INREG8(SRX + 1);
 	OUTREG8(SRX + 1, sr01 | (1 << 5));
 	usleep(30);
     }
 
-    OUTREG(VGACNTRL, VGA_DISP_DISABLE);
+    OUTREG(VGACNTRL, vgadisable);
     i830WaitForVblank(pScrn);
 
-    /* restore SR01 */
-    if (IS_G4X(pI830)) {
+    /* restore SR01 */{
 	OUTREG8(SRX, 1);
 	OUTREG8(SRX + 1, sr01);
     }