From cd1182f56a064d42d10e289ef4018f9c2230247d Mon Sep 17 00:00:00 2001
From: "Eric W. Biederman" <ebiederm@xmission.com>
Date: Wed, 4 Oct 2006 02:16:53 -0700
Subject: [PATCH] [PATCH] genirq: x86_64 irq: Kill irq compression

With more irqs in the system we don't need this.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rajesh Shah <rajesh.shah@intel.com>
Cc: Andi Kleen <ak@muc.de>
Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
 arch/x86_64/kernel/io_apic.c |  5 -----
 arch/x86_64/kernel/mpparse.c | 42 +-----------------------------------
 include/asm-x86_64/io_apic.h |  1 -
 3 files changed, 1 insertion(+), 47 deletions(-)

diff --git a/arch/x86_64/kernel/io_apic.c b/arch/x86_64/kernel/io_apic.c
index e076a8fa3ac3..7cc29b50b0c1 100644
--- a/arch/x86_64/kernel/io_apic.c
+++ b/arch/x86_64/kernel/io_apic.c
@@ -1415,8 +1415,6 @@ static inline void unlock_ExtINT_logic(void)
 	spin_unlock_irqrestore(&ioapic_lock, flags);
 }
 
-int timer_uses_ioapic_pin_0;
-
 /*
  * This code may look a bit paranoid, but it's supposed to cooperate with
  * a wide range of boards and BIOS bugs.  Fortunately only the timer IRQ
@@ -1453,9 +1451,6 @@ static inline void check_timer(void)
 	pin2  = ioapic_i8259.pin;
 	apic2 = ioapic_i8259.apic;
 
-	if (pin1 == 0)
-		timer_uses_ioapic_pin_0 = 1;
-
 	apic_printk(APIC_VERBOSE,KERN_INFO "..TIMER: vector=0x%02X apic1=%d pin1=%d apic2=%d pin2=%d\n",
 		vector, apic1, pin1, apic2, pin2);
 
diff --git a/arch/x86_64/kernel/mpparse.c b/arch/x86_64/kernel/mpparse.c
index b8d53dfa9931..b147ab19fbd4 100644
--- a/arch/x86_64/kernel/mpparse.c
+++ b/arch/x86_64/kernel/mpparse.c
@@ -790,20 +790,11 @@ void __init mp_config_acpi_legacy_irqs(void)
 	}
 }
 
-#define MAX_GSI_NUM	4096
-
 int mp_register_gsi(u32 gsi, int triggering, int polarity)
 {
 	int ioapic = -1;
 	int ioapic_pin = 0;
 	int idx, bit = 0;
-	static int pci_irq = 16;
-	/*
-	 * Mapping between Global System Interrupts, which
-	 * represent all possible interrupts, to the IRQs
-	 * assigned to actual devices.
-	 */
-	static int gsi_to_irq[MAX_GSI_NUM];
 
 	if (acpi_irq_model != ACPI_IRQ_MODEL_IOAPIC)
 		return gsi;
@@ -836,42 +827,11 @@ int mp_register_gsi(u32 gsi, int triggering, int polarity)
 	if ((1<<bit) & mp_ioapic_routing[ioapic].pin_programmed[idx]) {
 		Dprintk(KERN_DEBUG "Pin %d-%d already programmed\n",
 			mp_ioapic_routing[ioapic].apic_id, ioapic_pin);
-		return gsi_to_irq[gsi];
+		return gsi;
 	}
 
 	mp_ioapic_routing[ioapic].pin_programmed[idx] |= (1<<bit);
 
-	if (triggering == ACPI_LEVEL_SENSITIVE) {
-		/*
-		 * For PCI devices assign IRQs in order, avoiding gaps
-		 * due to unused I/O APIC pins.
-		 */
-		int irq = gsi;
-		if (gsi < MAX_GSI_NUM) {
-			/*
-			 * Retain the VIA chipset work-around (gsi > 15), but
-			 * avoid a problem where the 8254 timer (IRQ0) is setup
-			 * via an override (so it's not on pin 0 of the ioapic),
-			 * and at the same time, the pin 0 interrupt is a PCI
-			 * type.  The gsi > 15 test could cause these two pins
-			 * to be shared as IRQ0, and they are not shareable.
-			 * So test for this condition, and if necessary, avoid
-			 * the pin collision.
-			 */
-			if (gsi > 15 || (gsi == 0 && !timer_uses_ioapic_pin_0))
-				gsi = pci_irq++;
-			/*
-			 * Don't assign IRQ used by ACPI SCI
-			 */
-			if (gsi == acpi_fadt.sci_int)
-				gsi = pci_irq++;
-			gsi_to_irq[irq] = gsi;
-		} else {
-			printk(KERN_ERR "GSI %u is too high\n", gsi);
-			return gsi;
-		}
-	}
-
 	io_apic_set_pci_routing(ioapic, ioapic_pin, gsi,
 		triggering == ACPI_EDGE_SENSITIVE ? 0 : 1,
 		polarity == ACPI_ACTIVE_HIGH ? 0 : 1);
diff --git a/include/asm-x86_64/io_apic.h b/include/asm-x86_64/io_apic.h
index b26248b0e373..171ec2dc8c04 100644
--- a/include/asm-x86_64/io_apic.h
+++ b/include/asm-x86_64/io_apic.h
@@ -162,7 +162,6 @@ 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 */