Re: [patch] voluntary-preempt-2.6.8.1-P2

[Takashi Iwai]

At Wed, 18 Aug 2004 17:26:16 +0200,
Thomas Charbonnel wrote:
> 
> I was thinking more of something like this :
> 
> --- irq.c.orig  2004-08-16 14:26:34.000000000 +0200
> +++ irq.c       2004-08-18 17:23:18.011059064 +0200
> @@ -955,11 +955,16 @@
>                         return -EBUSY;
>                 }
> 
> -               /* add new interrupt at end of irq queue */
> -               do {
> -                       p = &old->next;
> -                       old = *p;
> -               } while (old);
> +               if (new->flags & SA_INTERRUPT)
> +                       /* add interrupt at the start of the queue */
> +                       new->next = old;
> +               else
> +                       /* add new interrupt at end of irq queue */
> +                       do {
> +                               p = &old->next;
> +                               old = *p;
> +                       } while (old);
> +
>                 shared = 1;
>         }

Ok, how about this one?  Together with your patch, the irq is turned
on for handlers without SA_INTERRUPT.


Takashi

--- linux/arch/i386/kernel/irq.c	2004-08-18 15:15:18.000000000 +0200
+++ linux/arch/i386/kernel/irq.c	2004-08-18 17:42:57.454819403 +0200
@@ -219,15 +219,23 @@ inline void synchronize_irq(unsigned int
 asmlinkage int handle_IRQ_event(unsigned int irq,
 		struct pt_regs *regs, struct irqaction *action)
 {
-	int status = 1;	/* Force the "do bottom halves" bit */
-	int retval = 0;
-
-	if (!(action->flags & SA_INTERRUPT))
-		local_irq_enable();
+	int status;
+	int ret, retval = 0;
+	int irq_off = 1;
 
+	status = 0;
 	do {
-		status |= action->flags;
-		retval |= action->handler(irq, action->dev_id, regs);
+		/* Assume that all SA_INTERRUPT handlers are at the head
+		 * of the irq queue
+		 */
+		if (irq_off && ! (action->flags & SA_INTERRUPT)) {
+			local_irq_enable();
+			irq_off = 0;
+		}
+		ret = action->handler(irq, action->dev_id, regs);
+		if (ret)
+			status |= action->flags;
+		retval |= ret;
 		action = action->next;
 	} while (action);
 	if (status & SA_SAMPLE_RANDOM)
@@ -955,11 +963,16 @@ int setup_irq(unsigned int irq, struct i
 			return -EBUSY;
 		}
 
-		/* add new interrupt at end of irq queue */
-		do {
-			p = &old->next;
-			old = *p;
-		} while (old);
+		if (new->flags & SA_INTERRUPT)
+			/* add interrupt at the start of the queue */
+			new->next = old;
+		else
+			/* add new interrupt at end of irq queue */
+			do {
+				p = &old->next;
+				old = *p;
+			} while (old);
+
 		shared = 1;
 	}
 
-
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