[PATCH] IA64: fix ISA IRQ trigger model and polarity setting

[Jiang Liu <liuj97@gmail.com>]

From: Liu Jiang <jiang.liu@huawei.com>

This bug interfered with another bug in QLA FC driver has caused big
trouble to us during the past month when validating a 32P Poulson
system with plenty of IO devices. Hope it could find its way into the
mainstream kernel. Thanks!

---

When handling Interrupt Source Override in MADT table, the default
ISA IRQ trigger model and poliarity should be edge-rising.
Current IA64 implmentation doesn't follow the specification and
set default ISA IRQ trigger model as level-low. With that wrong
configuration and when system runs out of interrupt vectors,
it will cause vector sharing among edge triggered ISA IRQ and
level triggered PCI IRQ, then interrupt storm. So change the code
to follow the specification.

Signed-off-by: Liu Jiang <jiang.liu@huawei.com>
---
 arch/ia64/kernel/acpi.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/ia64/kernel/acpi.c b/arch/ia64/kernel/acpi.c
index bfb4d01..18c33d6 100644
--- a/arch/ia64/kernel/acpi.c
+++ b/arch/ia64/kernel/acpi.c
@@ -349,11 +349,11 @@ acpi_parse_int_src_ovr(struct acpi_subtable_header * header,
 
 	iosapic_override_isa_irq(p->source_irq, p->global_irq,
 				 ((p->inti_flags & ACPI_MADT_POLARITY_MASK) ==
-				  ACPI_MADT_POLARITY_ACTIVE_HIGH) ?
-				 IOSAPIC_POL_HIGH : IOSAPIC_POL_LOW,
+				  ACPI_MADT_POLARITY_ACTIVE_LOW) ?
+				 IOSAPIC_POL_LOW : IOSAPIC_POL_HIGH,
 				 ((p->inti_flags & ACPI_MADT_TRIGGER_MASK) ==
-				 ACPI_MADT_TRIGGER_EDGE) ?
-				 IOSAPIC_EDGE : IOSAPIC_LEVEL);
+				 ACPI_MADT_TRIGGER_LEVEL) ?
+				 IOSAPIC_LEVEL : IOSAPIC_EDGE);
 	return 0;
 }
 
-- 
1.7.1