[PATCH 3/3] x86: when acpi_noirq is set, use mptable instead of MADT

When using pci=noacpi, or apci=noirq, acpi_noirq is set. We should skip
acpi_process_madt. Because it will set acpi_lapic and acpi_ioapic, at last
mptable is skipped, but we need io apic routing table in mptable.

Signed-off-by: Yinghai Lu <yinghai.lu@amd.com>

diff --git a/arch/i386/kernel/acpi/boot.c b/arch/i386/kernel/acpi/boot.c
index d12fb97..6d62dd1 100644
--- a/arch/i386/kernel/acpi/boot.c
+++ b/arch/i386/kernel/acpi/boot.c
@@ -1242,7 +1242,15 @@ int __init acpi_boot_init(void)
 	/*
 	 * Process the Multiple APIC Description Table (MADT), if present
 	 */
-	acpi_process_madt();
+	/* with acpi_noirq we don't need to process madt, it will set
+	 *	acpi_lapic and acpi_ioapic, they will make get_smp_config aka.
+	 *	MPTABLE be skipped and mp_irqs will not include entries for 
+	 *	irq routing for io apic, then pirq_enable_irq together with 
+	 * 	IO_APIC_get_PCI_irq_vector can not find irq in mp_irqs for 
+	 * 	devices that are using IOAPIC
+	 */
+	if(!acpi_noirq && !acpi_pci_disabled)
+		acpi_process_madt();
 
 	acpi_table_parse(ACPI_HPET, acpi_parse_hpet);