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=129623757413868Tested-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>

arch/x86/include/asm/acpi.h

@@ -88,6 +88,7 @@ extern int acpi_disabled;
 extern int acpi_pci_disabled;
 extern int acpi_skip_timer_override;
 extern int acpi_use_timer_override;
+extern int acpi_fix_pin2_polarity;
 
 extern u8 acpi_sci_flags;
 extern int acpi_sci_override_gsi;

arch/x86/kernel/acpi/boot.c

@@ -72,6 +72,7 @@ u8 acpi_sci_flags __initdata;
 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 @@ acpi_parse_int_src_ovr(struct acpi_subtable_header * header,
 		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,

arch/x86/kernel/early-quirks.c

@@ -143,15 +143,10 @@ static void __init ati_bugs(int num, int slot, int func)
 
 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;
 }
@@ -160,13 +155,16 @@ static void __init ati_bugs_contd(int num, int slot, int func)
 {
 	u32 d, rev;
 
-	if (acpi_use_timer_override)
-		return;
-
 	rev = ati_sbx00_rev(num, slot, func);
+	if (rev >= 0x40)
+		acpi_fix_pin2_polarity = 1;
+
 	if (rev > 0x13)
 		return;
 
+	if (acpi_use_timer_override)
+		return;
+
 	/* check for IRQ0 interrupt swap */
 	d = read_pci_config(num, slot, func, 0x64);
 	if (!(d & (1<<14)))