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SubjectRe: [patch 6/8] arm: ns9xxx: Remove private irq flow handler
Hi Thomas,

On Wed, Feb 02, 2011 at 09:41:27PM -0000, Thomas Gleixner wrote:
> handle_prio_irq is almost identical with handle_fasteoi_irq. The
> subtle differences are
> 1) The handler checks for IRQ_DISABLED after the device handler has
> been called. In case it's set it masks the interrupt.
>
> 2) When the handler sees IRQ_DISABLED on entry it masks the interupt
> in the same way as handle_fastoei_irq, but does not set the
> IRQ_PENDING flag.
>
> 3) Instead of gracefully handling a recursive interrupt it crashes the
> kernel.
>
> #1 is just relevant when a device handler calls disable_irq_nosync()
> and it does not matter whether we mask the interrupt right away or
> not. We handle lazy masking for disable_irq anyway, so there is no
> real reason to have this extra mask in place.
>
> #2 will prevent the resend of a pending interrupt, which can result in
> lost interrupts for edge type interrupts. For level type interrupts
> the resend is a noop in the generic code. According to the
> datasheet all interrupts are level type, so marking them as such
> will result in the exact same behaviour as the private
> handle_prio_irq implementation.
>
> #3 is just stupid. Crashing the kernel instead of handling a problem
> gracefully is just wrong. With the current semantics- all handlers
> run with interrupts disabled - this is even more wrong.
>
> Rename ack to eoi, remove the unused mask_ack, switch to
> handle_fasteoi_irq and remove the private function.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Cc: Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
> Cc: linux-arm-kernel@lists.infradead.org
I have no access to a ns9xxx machine, but this looks sane.

Acked-by: Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>

Thanks
Uwe

--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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