x86 quirk: Fix polarity for IRQ0 pin2 override on SB800 systems

On some SB800 systems polarity for IOAPIC pin2 is wrongly
specified as low active by BIOS. This caused system hangs after
resume from S3 when HPET was used in one-shot mode on such
systems because a timer interrupt was missed (HPET signal is
high active).

For more details see:

  http://marc.info/?l=linux-kernel&m=129623757413868

Tested-by: Manoj Iyer <manoj.iyer@canonical.com>
Tested-by: Andre Przywara <andre.przywara@amd.com>
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Borislav Petkov <borislav.petkov@amd.com>
Cc: stable@kernel.org # 37.x, 32.x
LKML-Reference: <20110224145346.GD3658@alberich.amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index b3a7113..3e6e2d6 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -72,6 +72,7 @@
 int acpi_sci_override_gsi __initdata;
 int acpi_skip_timer_override __initdata;
 int acpi_use_timer_override __initdata;
+int acpi_fix_pin2_polarity __initdata;
 
 #ifdef CONFIG_X86_LOCAL_APIC
 static u64 acpi_lapic_addr __initdata = APIC_DEFAULT_PHYS_BASE;
@@ -415,10 +416,15 @@
 		return 0;
 	}
 
-	if (acpi_skip_timer_override &&
-	    intsrc->source_irq == 0 && intsrc->global_irq == 2) {
-		printk(PREFIX "BIOS IRQ0 pin2 override ignored.\n");
-		return 0;
+	if (intsrc->source_irq == 0 && intsrc->global_irq == 2) {
+		if (acpi_skip_timer_override) {
+			printk(PREFIX "BIOS IRQ0 pin2 override ignored.\n");
+			return 0;
+		}
+		if (acpi_fix_pin2_polarity && (intsrc->inti_flags & ACPI_MADT_POLARITY_MASK)) {
+			intsrc->inti_flags &= ~ACPI_MADT_POLARITY_MASK;
+			printk(PREFIX "BIOS IRQ0 pin2 override: forcing polarity to high active.\n");
+		}
 	}
 
 	mp_override_legacy_irq(intsrc->source_irq,
diff --git a/arch/x86/kernel/early-quirks.c b/arch/x86/kernel/early-quirks.c
index 76b8cd9..9efbdcc 100644
--- a/arch/x86/kernel/early-quirks.c
+++ b/arch/x86/kernel/early-quirks.c
@@ -143,15 +143,10 @@
 
 static u32 __init ati_sbx00_rev(int num, int slot, int func)
 {
-	u32 old, d;
+	u32 d;
 
-	d = read_pci_config(num, slot, func, 0x70);
-	old = d;
-	d &= ~(1<<8);
-	write_pci_config(num, slot, func, 0x70, d);
 	d = read_pci_config(num, slot, func, 0x8);
 	d &= 0xff;
-	write_pci_config(num, slot, func, 0x70, old);
 
 	return d;
 }
@@ -160,11 +155,14 @@
 {
 	u32 d, rev;
 
-	if (acpi_use_timer_override)
+	rev = ati_sbx00_rev(num, slot, func);
+	if (rev >= 0x40)
+		acpi_fix_pin2_polarity = 1;
+
+	if (rev > 0x13)
 		return;
 
-	rev = ati_sbx00_rev(num, slot, func);
-	if (rev > 0x13)
+	if (acpi_use_timer_override)
 		return;
 
 	/* check for IRQ0 interrupt swap */