linux-kernel - Why does handle_simple_irq() require IRQ's to be disabled?

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Date:	Mon, 6 Jun 2011 17:28:40 +0200
From:	David Jander <david.jander@...tonic.nl>
To:	linux-kernel@...r.kernel.org
Cc:	Thomas Gleixner <tglx@...utronix.de>
Subject: Why does handle_simple_irq() require IRQ's to be disabled?

Hi,

I am trying to implement/fix interrupt controller functionality in
gpio/pca953x.c, and for some reason which I don't understand, I need to disable
interrupts with local_irq_disable() before calling generic_handle_irq(). This
does not seem right.
If I follow the code of handle_simple_irq(), the handler function setup for
this IRQ, I get to handle_irq_event_percpu(), which has a
WARN_ONCE(!irqs_disabled(),...
This WARN is triggered, since nobody explicitly disables interrupts. Why?

generic_hanlde_irq() is called from a threaded interrupt handler of the parent
of this interrupt controller, and calling local_irq_disable() here seems like
a crime. What am I doing wrong?

Best regards,

-- 
David Jander
Protonic Holland.
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