Patch by Ivan Kokshaysky originally posted to axp-list@redhat.com, updated
to cleanly apply to X.Org CVS by Mike A. Harris <mharris@redhat.com>

Problems covered:
* Detection of the primary adapter is broken. You have to
  set explicit PCI id in XF86Config to get the card detected
  as *secondary*. However, switching to VGA text console won't work then
  (most drivers don't save/restore VGA state for secondary adapters).
* Rather old bug in mga driver (since 4.1.0, IIRC) - the driver
  attempts to read the video ROM *before* enabling it. Naturally,
  this causes annoying machine check on certain platforms.
	  
This patch fixes the following:
	https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=91711

Submitted upstream on Jul 9, 2004 by Mike Harris:
	http://freedesktop.org/bugzilla/show_bug.cgi?id=843

--- xc.orig/programs/Xserver/hw/xfree86/drivers/mga/mga_driver.c	2004-06-16 05:44:00.000000000 -0400
+++ xc/programs/Xserver/hw/xfree86/drivers/mga/mga_driver.c	2004-07-09 04:25:18.000000000 -0400
@@ -712,10 +712,6 @@
 	pBios = &pMga->Bios;
 	pBios2 = &pMga->Bios2;
         
-	/* Get the output mode set by the BIOS */
-	xf86ReadDomainMemory(pMga->PciTag, pMga->BiosAddress + 0x7ff1u,
-			     sizeof(CARD8), &pMga->BiosOutputMode); 
-
 	/*
 	 * If the BIOS address was probed, it was found from the PCI config
 	 * space.  If it was given in the config file, try to guess when it
@@ -739,6 +735,9 @@
 		return;
 	}
         
+	/* Get the output mode set by the BIOS */
+	pMga->BiosOutputMode = BIOS[0x7ff1];
+
         /* Get the video BIOS info block */
 	if (strncmp((char *)(&BIOS[45]), "MATROX", 6)) {
 		xf86DrvMsg(pScrn->scrnIndex, X_WARNING,
--- xc.orig/programs/Xserver/hw/xfree86/common/xf86pciBus.c	2004-07-06 10:37:47.000000000 -0400
+++ xc/programs/Xserver/hw/xfree86/common/xf86pciBus.c	2004-07-09 04:25:18.000000000 -0400
@@ -424,7 +424,7 @@
 	    if ((pcrp->pci_command & PCI_CMD_MEM_ENABLE) &&
 		(num == 1 ||
 		 ((info->class == PCI_CLASS_DISPLAY) &&
-		  (info->subclass == PCI_SUBCLASS_DISPLAY_MISC)))) {
+		  (info->subclass == PCI_SUBCLASS_DISPLAY_VGA)))) {
 		if (primaryBus.type == BUS_NONE) {
 		    primaryBus.type = BUS_PCI;
 		    primaryBus.id.pci.bus = pcrp->busnum;