This patch reads and stores host bridge resources reported by
ACPI BIOS for x86_64 systems. This is needed since ACPI hotplug
code now uses the PCI core for resource management. This patch
simply adds the boot parameter (acpi=root_resources) to enable
the functionality that is implemented in arch/i386.

Signed-off-by: Rajesh Shah <rajesh.shah@intel.com>

Index: linux-2.6.12-rc4-mm2/include/asm-x86_64/acpi.h
===================================================================
--- linux-2.6.12-rc4-mm2.orig/include/asm-x86_64/acpi.h
+++ linux-2.6.12-rc4-mm2/include/asm-x86_64/acpi.h
@@ -143,10 +143,16 @@ static inline void acpi_disable_pci(void
 	acpi_noirq_set();
 }
 extern int acpi_irq_balance_set(char *str);
+extern int acpi_read_root_resources;
+static inline void acpi_set_read_root_resources(void)
+{
+	acpi_read_root_resources = 1;
+}
 #else
 static inline void acpi_noirq_set(void) { }
 static inline void acpi_disable_pci(void) { }
 static inline int acpi_irq_balance_set(char *str) { return 0; }
+static inline void acpi_set_read_root_resources(void) { }
 #endif
 
 #ifdef CONFIG_ACPI_SLEEP
Index: linux-2.6.12-rc4-mm2/arch/x86_64/kernel/setup.c
===================================================================
--- linux-2.6.12-rc4-mm2.orig/arch/x86_64/kernel/setup.c
+++ linux-2.6.12-rc4-mm2/arch/x86_64/kernel/setup.c
@@ -319,6 +319,9 @@ static __init void parse_cmdline_early (
 			acpi_disable_pci();
 		else if (!memcmp(from, "acpi=noirq", 10))
 			acpi_noirq_set();
+		/* Use ACPI to read host bridge resources */
+		else if (!memcmp(from, "acpi=root_resources", 19))
+			acpi_set_read_root_resources();
 
 		else if (!memcmp(from, "acpi_sci=edge", 13))
 			acpi_sci_flags.trigger =  1;

--