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

[Manoj Iyer]

From: Andreas Herrmann <andreas.herrmann3 at amd.com>

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 at canonical.com>
Tested-by: Andre Przywara <andre.przywara at amd.com>
Signed-off-by: Andreas Herrmann <andreas.herrmann3 at amd.com>
Cc: Borislav Petkov <borislav.petkov at amd.com>
Cc: stable at kernel.org # 37.x, 32.x
LKML-Reference: <20110224145346.GD3658 at alberich.amd.com>
Signed-off-by: Ingo Molnar <mingo at elte.hu>
(cherry picked from commit 7f74f8f28a2bd9db9404f7d364e2097a0c42cc12)

Signed-off-by: Manoj Iyer <manoj.iyer at canonical.com>
---
 arch/x86/include/asm/acpi.h    |    1 +
 arch/x86/kernel/acpi/boot.c    |   14 ++++++++++----
 arch/x86/kernel/early-quirks.c |   16 +++++++---------
 3 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/arch/x86/include/asm/acpi.h b/arch/x86/include/asm/acpi.h
index 211ca3f..4ea15ca 100644
--- a/arch/x86/include/asm/acpi.h
+++ b/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;
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index b4d3c50..7d3ac5a 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/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,
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 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)))
-- 
1.7.1