On Fri, 12 Oct 2012, Liu, Chuansheng wrote:
> > -----Original Message-----
> > From: Thomas Gleixner [mailto:t...@linutronix.de]
> > Sent: Friday, October 12, 2012 8:32 PM
> > To: Liu, Chuansheng
> > Cc: linux-kernel@vger.kernel.org
> > Subject: Re: [PATCH] genirq: for edge interrupt IRQS_ONESHOT support with
> > irq
> > thread
> >
> > On Fri, 12 Oct 2012, Chuansheng Liu wrote:
> > >
> > > In our system, there is one edge interrupt, and we want it to be
> > > irq thread with IRQS_ONESHOT, and found in handle_edge_irq(),
> > > even with IRQS_ONESHOT, the irq is still unmasked without care of
> > > flag IRQS_ONESHOT.
> > >
> > > It causes IRQS_ONESHOT can not work well for edge interrupt, but also
> > > after the irq thread finished with flag IRQS_ONESHOT, the irq will be
> > > possible to be unmasked again, it should be messing mask/unmask logic.
> >
> > This is just wrong. By masking edge interrupts you will run into
> > situations where you will lose interrupts.
> >
> > Can you please explain, why you want to mask your edge interrupt?
> When I request_irq with irq thread handler and flag IRQS_ONESHOT, if
> do not mask the edge interrupt, the primary handler and irq thread
> maybe run at the same time, and in my real case it causes spin
> deadlock.
Then your code is simply wrong and you need to fix it instead of hacking a
workaround into the core code. Locking is not that hard.
> You means it is not right with IRQS_ONESHOT for edge interrupt?
It's wrong. Simnply because you can lose interrupts.
interrupt raised
handle_edge_irq()
mask_ack_irq()
handle_event()
wake irq thread
reti
irq thread runs
handle device interrupt()
<--- device issues edge irq
unmask_irq()
This interrupt is not delivered. So your device stops working. Not
what you want, right?
Thanks,
tglx
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
