Patch by Kevin E. Martin <kem@redhat.com> based off a patch from Dell,
which changes the X server to use Linux native /proc based PCI
interfaces by default instead of bitbanging PCI config space directly.

Patch updated by Olivier Baudron <olivier.baudron@m4x.org> to fix all
occurrences of PCI config space access.

This fixes a problem in Linux where other software may be probing PCI
config space using the native interfaces correctly and the kernel PCI
lock is held, then the X server starts up and simultaneously stomps on
PCI space, generally causing the machine to hang.

Fixes bugs:
	https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=152608
	https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=118130

This may also fix the following bugs (unconfirmed):
	https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=146386

Update: This is a forward port of a patch we added to XFree86-4.3.0 for
RHEL-3.  The only modification is the changes to xf86Globals.c were
dropped, as they're included in xorg-x11 stock code already.

    Mike A. Harris <mharris@redhat.com>

This bug is nominated for the 6.8.3 release as attachment 2285.
	https://bugs.freedesktop.org/show_bug.cgi?id=2880


--- xc/programs/Xserver/hw/xfree86/int10/helper_exec.c.use-linux-native-pciscan-by-default	2004-04-23 15:54:06.000000000 -0400
+++ xc/programs/Xserver/hw/xfree86/int10/helper_exec.c	2005-07-27 16:41:26.000000000 -0400
@@ -23,10 +23,12 @@
 #include "int10Defines.h"
 #include "xf86int10.h"
 
-#if !defined (_PC) && !defined (_PC_PCI)
 static int pciCfg1in(CARD16 addr, CARD32 *val);
 static int pciCfg1out(CARD16 addr, CARD32 val);
-#endif
+static int pciCfg1inw(CARD16 addr, CARD16 *val);
+static int pciCfg1outw(CARD16 addr, CARD16 val);
+static int pciCfg1inb(CARD16 addr, CARD8 *val);
+static int pciCfg1outb(CARD16 addr, CARD8 val);
 #if defined (_PC)
 static void SetResetBIOSVars(xf86Int10InfoPtr pInt, Bool set);
 #endif
@@ -321,7 +323,8 @@
 	}
 #endif /* __NOT_YET__ */
     } else {
-	val = inb(Int10Current->ioBase + port);
+	if (!pciCfg1inb(port, &val))
+	    val = inb(Int10Current->ioBase + port);
 #ifdef PRINT_PORT
 	ErrorF(" inb(%#x) = %2.2x\n", port, val);
 #endif
@@ -343,7 +346,8 @@
 	(void)getsecs(&sec, &usec);
 	val = (CARD16)(usec / 3);
     } else {
-	val = inw(Int10Current->ioBase + port);
+	if (!pciCfg1inw(port, &val))
+	    val = inw(Int10Current->ioBase + port);
     }
 #ifdef PRINT_PORT
     ErrorF(" inw(%#x) = %4.4x\n", port, val);
@@ -380,7 +384,8 @@
 #ifdef PRINT_PORT
 	ErrorF(" outb(%#x, %2.2x)\n", port, val);
 #endif
-	outb(Int10Current->ioBase + port, val);
+	if (!pciCfg1outb(port, val))
+	    outb(Int10Current->ioBase + port, val);
     }
 }
 
@@ -391,7 +396,8 @@
     ErrorF(" outw(%#x, %4.4x)\n", port, val);
 #endif
 
-    outw(Int10Current->ioBase + port, val);
+    if (!pciCfg1outw(port, val))
+	outw(Int10Current->ioBase + port, val);
 }
 
 CARD32
@@ -399,10 +405,8 @@
 {
     CARD32 val;
 
-#if !defined(_PC) && !defined(_PC_PCI)
     if (!pciCfg1in(port, &val))
-#endif
-    val = inl(Int10Current->ioBase + port);
+	val = inl(Int10Current->ioBase + port);
 
 #ifdef PRINT_PORT
     ErrorF(" inl(%#x) = %8.8x\n", port, val);
@@ -417,10 +421,8 @@
     ErrorF(" outl(%#x, %8.8x)\n", port, val);
 #endif
 
-#if !defined(_PC) && !defined(_PC_PCI)
     if (!pciCfg1out(port, val))
-#endif
-    outl(Int10Current->ioBase + port, val);
+	outl(Int10Current->ioBase + port, val);
 }
 
 CARD8
@@ -459,7 +461,6 @@
     (*Int10Current->mem->wl)(Int10Current, addr, val);
 }
 
-#if !defined(_PC) && !defined(_PC_PCI)
 static CARD32 PciCfg1Addr = 0;
 
 #define TAG(Cfg1Addr) (Cfg1Addr & 0xffff00)
@@ -487,12 +488,85 @@
 	return 1;
     }
     if (addr == 0xCFC) {
-	pciWriteLong(TAG(PciCfg1Addr), OFFSET(PciCfg1Addr),val);
+	pciWriteLong(TAG(PciCfg1Addr), OFFSET(PciCfg1Addr), val);
+	return 1;
+    }
+    return 0;
+}
+
+static int
+pciCfg1inw(CARD16 addr, CARD16 *val)
+{
+    int offset, shift;
+
+    if ((addr >= 0xCF8) && (addr <= 0xCFB)) {
+	shift = (addr - 0xCF8) * 8;
+	*val = (PciCfg1Addr >> shift) & 0xffff;
+	return 1;
+    }
+    if ((addr >= 0xCFC) && (addr <= 0xCFF)) {
+	offset = addr - 0xCFC;
+	*val = pciReadWord(TAG(PciCfg1Addr), OFFSET(PciCfg1Addr) + offset);
+	return 1;
+    }
+    return 0;
+}
+
+static int
+pciCfg1outw(CARD16 addr, CARD16 val)
+{
+    int offset, shift;
+
+    if ((addr >= 0xCF8) && (addr <= 0xCFB)) {
+	shift = (addr - 0xCF8) * 8;
+	PciCfg1Addr &= ~(0xffff << shift);
+	PciCfg1Addr |= ((CARD32) val) << shift;
+	return 1;
+    }
+    if ((addr >= 0xCFC) && (addr <= 0xCFF)) {
+	offset = addr - 0xCFC;
+	pciWriteWord(TAG(PciCfg1Addr), OFFSET(PciCfg1Addr) + offset, val);
+	return 1;
+    }
+    return 0;
+}
+
+static int
+pciCfg1inb(CARD16 addr, CARD8 *val)
+{
+    int offset, shift;
+
+    if ((addr >= 0xCF8) && (addr <= 0xCFB)) {
+	shift = (addr - 0xCF8) * 8;
+	*val = (PciCfg1Addr >> shift) & 0xff;
+	return 1;
+    }
+    if ((addr >= 0xCFC) && (addr <= 0xCFF)) {
+	offset = addr - 0xCFC;
+	*val = pciReadByte(TAG(PciCfg1Addr), OFFSET(PciCfg1Addr) + offset);
+	return 1;
+    }
+    return 0;
+}
+
+static int
+pciCfg1outb(CARD16 addr, CARD8 val)
+{
+    int offset, shift;
+
+    if ((addr >= 0xCF8) && (addr <= 0xCFB)) {
+	shift = (addr - 0xCF8) * 8;
+	PciCfg1Addr &= ~(0xff << shift);
+	PciCfg1Addr |= ((CARD32) val) << shift;
+	return 1;
+    }
+    if ((addr >= 0xCFC) && (addr <= 0xCFF)) {
+	offset = addr - 0xCFC;
+	pciWriteByte(TAG(PciCfg1Addr), OFFSET(PciCfg1Addr) + offset, val);
 	return 1;
     }
     return 0;
 }
-#endif
 
 CARD8
 bios_checksum(CARD8 *start, int size)