linux-kernel - Re: [PATCH] genirq: irq_chip->startup() usage in setup_irq and set_irq

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Date:	Sat, 6 Sep 2008 20:37:18 +0200
From:	Ingo Molnar <mingo@...e.hu>
To:	Pawel MOLL <pawel.moll@...com>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] genirq: irq_chip->startup() usage in setup_irq and
	set_irq_chained handler


* Pawel MOLL <pawel.moll@...com> wrote:

> This patch clarifies usage of irq_chip->startup() callback:
> 
> 1. The "if (startup) startup(); else enabled();" code in setup_irq()
>    is unnecessary, as startup() falls back to enabled() via
>    default callbacks, set by irq_chip_set_defaults().
> 
> 2. When using set_irq_chained_handler() the startup() was never called,
>    which is not good at all... Fixed. And again - when startup() is not
>    defined the call will fall back to enable() than to unmask() via
>    default callbacks.
> 
> Signed-off-by: Pawel Moll <pawel.moll@...com>
> Acked-by: Benjamin Herrenschmidt <benh@...nel.crashing.org>

applied the commit below to tip/genirq - thanks Pawel.

	Ingo

------------->
>From 7e6e178ab1548c8d894a77593e757acf4510b8ba Mon Sep 17 00:00:00 2001
From: Pawel MOLL <pawel.moll@...com>
Date: Mon, 1 Sep 2008 10:12:11 +0100
Subject: [PATCH] genirq: irq_chip->startup() usage in setup_irq and set_irq_chained handler

This patch clarifies usage of irq_chip->startup() callback:

1. The "if (startup) startup(); else enabled();" code in setup_irq()
   is unnecessary, as startup() falls back to enabled() via
   default callbacks, set by irq_chip_set_defaults().

2. When using set_irq_chained_handler() the startup() was never called,
   which is not good at all... Fixed. And again - when startup() is not
   defined the call will fall back to enable() than to unmask() via
   default callbacks.

Signed-off-by: Pawel Moll <pawel.moll@...com>
Acked-by: Benjamin Herrenschmidt <benh@...nel.crashing.org>
Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
 kernel/irq/chip.c   |    2 +-
 kernel/irq/manage.c |    5 +----
 2 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 964964b..240c64d 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -587,7 +587,7 @@ __set_irq_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
 		desc->status &= ~IRQ_DISABLED;
 		desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
 		desc->depth = 0;
-		desc->chip->unmask(irq);
+		desc->chip->startup(irq);
 	}
 	spin_unlock_irqrestore(&desc->lock, flags);
 }
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index ae1b684..9aa3e7b 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -397,10 +397,7 @@ int setup_irq(unsigned int irq, struct irqaction *new)
 		if (!(desc->status & IRQ_NOAUTOEN)) {
 			desc->depth = 0;
 			desc->status &= ~IRQ_DISABLED;
-			if (desc->chip->startup)
-				desc->chip->startup(irq);
-			else
-				desc->chip->enable(irq);
+			desc->chip->startup(irq);
 		} else
 			/* Undo nested disables: */
 			desc->depth = 1;
--
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