From: Prarit Bhargava <prarit@redhat.com>
Date: Wed, 14 May 2008 12:57:54 -0400
Subject: [ia64] properly unregister legacy interrupts
Message-id: 20080514165736.21362.88497.sendpatchset@prarit.bos.redhat.com
O-Subject: [RHEL5 PATCH]: Properly unregister legacy interrupts
Bugzilla: 445886
RH-Acked-by: Larry Woodman <lwoodman@redhat.com>
RH-Acked-by: Larry Woodman <lwoodman@redhat.com>
RH-Acked-by: Larry Woodman <lwoodman@redhat.com>
RH-Acked-by: Brian Maly <bmaly@redhat.com>

Backport of

http://marc.info/?l=linux-ia64&m=121078083124228&w=2

When unloading the uhci_hcd module on Hitachi ia64 hardware, false warnings
are output to the console.

acpi_unregister_gsi() should "undo" what acpi_register_gsi() does.

On systems that have legacy interrupts, acpi_unregister_gsi erroneously calls
iosapci_unregister_intr() which is wrong to do and causes a loud warning.

acpi_unregister_gsi() should just return in these cases.

Resolves BZ 445885.

Successfully tested by me.

 arch/ia64/kernel/acpi.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/arch/ia64/kernel/acpi.c b/arch/ia64/kernel/acpi.c
index c9e3aae..97c2fbd 100644
--- a/arch/ia64/kernel/acpi.c
+++ b/arch/ia64/kernel/acpi.c
@@ -621,6 +621,9 @@ void acpi_unregister_gsi(u32 gsi)
 	if (acpi_irq_model == ACPI_IRQ_MODEL_PLATFORM)
 		return;
 
+	if (has_8259 && gsi < 16)
+		return;
+
 	iosapic_unregister_intr(gsi);
 }