Re: [PATCH] irq: Add a new IRQF_ACK_BEFORE_UNMASK irq flag

From: Thomas Gleixner
Date: Thu Mar 13 2014 - 09:33:02 EST


On Thu, 13 Mar 2014, Sebastian Andrzej Siewior wrote:

> * Thomas Gleixner | 2014-03-12 11:38:24 [+0100]:
>
> >Untested patch below.
> Tested-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
>
> on DA850 / OMAP-L138. Without:
> 59: 560 cp_intc ohci_hcd:usb2
> with the patch
> 59: 280 cp_intc ohci_hcd:usb2
>
> that makes a difference of 280 interrupts. Prior the patch each
> interrupt was handled twice and returned once with IRQ_HANDLED and the
> second time with IRQ_NONE. With the proper EOI ack I don't see the
> IRQ_NONE anymore.

Right. The documentation of L138 clearly says, that you need to ack
the interrupt AFTER the handler has run. But the driver uses
handle_edge_irq, which acks BEFORE the handler has run.

Quality stuff.

Thanks,

tglx






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