1 files changed, 28 insertions, 14 deletions

diff --git a/arch/x86/kernel/io_apic_32.c b/arch/x86/kernel/io_apic_32.c
index 337ec3438a8..558abf4c796 100644
--- a/arch/x86/kernel/io_apic_32.c
+++ b/arch/x86/kernel/io_apic_32.c
@@ -1569,7 +1569,7 @@ void /*__init*/ print_local_APIC(void *dummy)
 
 void print_all_local_APICs(void)
 {
-	on_each_cpu(print_local_APIC, NULL, 1, 1);
+	on_each_cpu(print_local_APIC, NULL, 1);
 }
 
 void /*__init*/ print_PIC(void)
@@ -2020,7 +2020,7 @@ static inline void init_IO_APIC_traps(void)
  * The local APIC irq-chip implementation:
  */
 
-static void ack_apic(unsigned int irq)
+static void ack_lapic_irq(unsigned int irq)
 {
 	ack_APIC_irq();
 }
@@ -2045,9 +2045,17 @@ static struct irq_chip lapic_chip __read_mostly = {
 	.name		= "local-APIC",
 	.mask		= mask_lapic_irq,
 	.unmask		= unmask_lapic_irq,
-	.eoi		= ack_apic,
+	.ack		= ack_lapic_irq,
 };
 
+static void lapic_register_intr(int irq, int vector)
+{
+	irq_desc[irq].status &= ~IRQ_LEVEL;
+	set_irq_chip_and_handler_name(irq, &lapic_chip, handle_edge_irq,
+				      "edge");
+	set_intr_gate(vector, interrupt[irq]);
+}
+
 static void __init setup_nmi(void)
 {
 	/*
@@ -2247,8 +2255,7 @@ static inline void __init check_timer(void)
 
 	printk(KERN_INFO "...trying to set up timer as Virtual Wire IRQ...");
 
-	set_irq_chip_and_handler_name(0, &lapic_chip, handle_fasteoi_irq,
-				      "fasteoi");
+	lapic_register_intr(0, vector);
 	apic_write_around(APIC_LVT0, APIC_DM_FIXED | vector);	/* Fixed mode */
 	enable_8259A_irq(0);
 
@@ -2280,11 +2287,21 @@ out:
 }
 
 /*
- *
- * IRQ's that are handled by the PIC in the MPS IOAPIC case.
- * - IRQ2 is the cascade IRQ, and cannot be a io-apic IRQ.
- *   Linux doesn't really care, as it's not actually used
- *   for any interrupt handling anyway.
+ * Traditionally ISA IRQ2 is the cascade IRQ, and is not available
+ * to devices.  However there may be an I/O APIC pin available for
+ * this interrupt regardless.  The pin may be left unconnected, but
+ * typically it will be reused as an ExtINT cascade interrupt for
+ * the master 8259A.  In the MPS case such a pin will normally be
+ * reported as an ExtINT interrupt in the MP table.  With ACPI
+ * there is no provision for ExtINT interrupts, and in the absence
+ * of an override it would be treated as an ordinary ISA I/O APIC
+ * interrupt, that is edge-triggered and unmasked by default.  We
+ * used to do this, but it caused problems on some systems because
+ * of the NMI watchdog and sometimes IRQ0 of the 8254 timer using
+ * the same ExtINT cascade interrupt to drive the local APIC of the
+ * bootstrap processor.  Therefore we refrain from routing IRQ2 to
+ * the I/O APIC in all cases now.  No actual device should request
+ * it anyway.  --macro
  */
 #define PIC_IRQS	(1 << PIC_CASCADE_IR)
 
@@ -2298,10 +2315,7 @@ void __init setup_IO_APIC(void)
 
 	enable_IO_APIC();
 
-	if (acpi_ioapic)
-		io_apic_irqs = ~0;	/* all IRQs go through IOAPIC */
-	else
-		io_apic_irqs = ~PIC_IRQS;
+	io_apic_irqs = ~PIC_IRQS;
 
 	printk("ENABLING IO-APIC IRQs\n");