Messages in this thread | | | Date | Thu, 3 Feb 2011 08:56:23 +0100 | From | Uwe Kleine-König <> | Subject | Re: [patch 6/8] arm: ns9xxx: Remove private irq flow handler |
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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/ | -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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