[PATCH] Fix irq handling of IO-APIC edge IRQs on UP

send_IPI_self is needed to resend irqs with IRQ_PENDING status when
enabled.

Checked with Ingo, and it's in 2.4-ac for some time.

This should fix ide lost interrupts on UP with IO-APIC

Ide trigers it this way:
 - disable_irq
 - do stuff that triggers IRQ.
 - irq is IRQ_PENDING
 - enable_irq
 - IRQ is lost, needs to be resend.

I'll send the patch to fixup IDE disable_irq logic to Bart.

arch/i386/kernel/io_apic.c

@@ -682,6 +682,21 @@ __initcall(balanced_irq_init);
 
 #else /* !SMP */
 static inline void move_irq(int irq) { }
+
+void send_IPI_self(int vector)
+{
+	unsigned int cfg;
+
+	/*
+	 * Wait for idle.
+	 */
+	apic_wait_icr_idle();
+	cfg = APIC_DM_FIXED | APIC_DEST_SELF | vector | APIC_DEST_LOGICAL;
+	/*
+	 * Send the IPI. The write to APIC_ICR fires this off.
+	 */
+	apic_write_around(APIC_ICR, cfg);
+}
 #endif /* defined(CONFIG_SMP) */
 
 

include/asm-i386/hw_irq.h

@@ -107,7 +107,7 @@ static inline void x86_do_profile(struct pt_regs * regs)
 	atomic_inc((atomic_t *)&prof_buffer[eip]);
 }
  
-#if defined(CONFIG_X86_IO_APIC) && defined(CONFIG_SMP)
+#if defined(CONFIG_X86_IO_APIC)
 static inline void hw_resend_irq(struct hw_interrupt_type *h, unsigned int i)
 {
 	if (IO_APIC_IRQ(i))