Revert "PCI: use ACPI _CRS data by default"

This reverts commit 9e9f46c44e487af0a82eb61b624553e2f7118f5b.

Quoting from the commit message:

 "At this point, it seems to solve more problems than it causes, so let's
  try using it by default.  It's an easy revert if it ends up causing
  trouble."

And guess what? The _CRS code causes trouble.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/kernel-parameters.txt

@@ -1855,7 +1855,7 @@ and is between 256 and 4096 characters. It is defined in the file
 				IRQ routing is enabled.
 		noacpi		[X86] Do not use ACPI for IRQ routing
 				or for PCI scanning.
-		nocrs		[X86] Don't use _CRS for PCI resource
+		use_crs		[X86] Use _CRS for PCI resource
 				allocation.
 		routeirq	Do IRQ routing for all PCI devices.
 				This is normally done in pci_enable_device(),

arch/x86/include/asm/pci_x86.h

@@ -25,7 +25,7 @@
 #define PCI_BIOS_IRQ_SCAN	0x2000
 #define PCI_ASSIGN_ALL_BUSSES	0x4000
 #define PCI_CAN_SKIP_ISA_ALIGN	0x8000
-#define PCI_NO_ROOT_CRS		0x10000
+#define PCI_USE__CRS		0x10000
 #define PCI_CHECK_ENABLE_AMD_MMCONF	0x20000
 #define PCI_HAS_IO_ECS		0x40000
 #define PCI_NOASSIGN_ROMS	0x80000

arch/x86/pci/acpi.c

@@ -238,7 +238,7 @@ struct pci_bus * __devinit pci_acpi_scan_root(struct acpi_device *device, int do
 #endif
 	}
 
-	if (bus && !(pci_probe & PCI_NO_ROOT_CRS))
+	if (bus && (pci_probe & PCI_USE__CRS))
 		get_current_resources(device, busnum, domain, bus);
 	return bus;
 }

arch/x86/pci/amd_bus.c

@@ -101,7 +101,7 @@ void x86_pci_root_bus_res_quirks(struct pci_bus *b)
 	struct pci_root_info *info;
 
 	/* don't go for it if _CRS is used */
-	if (!(pci_probe & PCI_NO_ROOT_CRS))
+	if (pci_probe & PCI_USE__CRS)
 		return;
 
 	/* if only one root bus, don't need to anything */

arch/x86/pci/common.c

@@ -515,8 +515,8 @@ char * __devinit  pcibios_setup(char *str)
 	} else if (!strcmp(str, "assign-busses")) {
 		pci_probe |= PCI_ASSIGN_ALL_BUSSES;
 		return NULL;
-	} else if (!strcmp(str, "nocrs")) {
-		pci_probe |= PCI_NO_ROOT_CRS;
+	} else if (!strcmp(str, "use_crs")) {
+		pci_probe |= PCI_USE__CRS;
 		return NULL;
 	} else if (!strcmp(str, "earlydump")) {
 		pci_early_dump_regs = 1;