[PATCH] x86_64: avoid IRQ0 ioapic pin collision

The patch addresses a problem with ACPI SCI interrupt entry, which gets
re-used, and the IRQ is assigned to another unrelated device.  The patch
corrects the code such that SCI IRQ is skipped and duplicate entry is
avoided.  Second issue came up with VIA chipset, the problem was caused by
original patch assigning IRQs starting 16 and up.  The VIA chipset uses
4-bit IRQ register for internal interrupt routing, and therefore cannot
handle IRQ numbers assigned to its devices.  The patch corrects this
problem by allowing PCI IRQs below 16.

Cc: len.brown@intel.com

Signed-off by: Natalie Protasevich <Natalie.Protasevich@unisys.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 2 insertions, 0 deletions

diff --git a/include/asm-i386/io_apic.h b/include/asm-i386/io_apic.h
index 51c4e5fe6062..d92e253f7f6f 100644
--- a/include/asm-i386/io_apic.h
+++ b/include/asm-i386/io_apic.h
@@ -200,6 +200,7 @@ extern int io_apic_get_unique_id (int ioapic, int apic_id);
 extern int io_apic_get_version (int ioapic);
 extern int io_apic_get_redir_entries (int ioapic);
 extern int io_apic_set_pci_routing (int ioapic, int pin, int irq, int edge_level, int active_high_low);
+extern int timer_uses_ioapic_pin_0;
 #endif /* CONFIG_ACPI */
 
 extern int (*ioapic_renumber_irq)(int ioapic, int irq);
diff --git a/include/asm-x86_64/io_apic.h b/include/asm-x86_64/io_apic.h
index ee1bc69aec9c..52484e82c641 100644
--- a/include/asm-x86_64/io_apic.h
+++ b/include/asm-x86_64/io_apic.h
@@ -205,6 +205,7 @@ extern int skip_ioapic_setup;
 extern int io_apic_get_version (int ioapic);
 extern int io_apic_get_redir_entries (int ioapic);
 extern int io_apic_set_pci_routing (int ioapic, int pin, int irq, int, int);
+extern int timer_uses_ioapic_pin_0;
 #endif
 
 extern int sis_apic_bug; /* dummy */