Messages in this thread |  | | | Date | Thu, 3 Jul 2008 14:11:22 +0900 | | From | "Magnus Damm" <> | | Subject | Re: [PATCH] uio: User IRQ Mode | |
On Wed, Jul 2, 2008 at 8:31 PM, Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
>> Note that the irq is disabled instead of acked. So this should not be a
>> problem. The userspace part then is responsible to ack (first) and
>> unmask the irq.
>
> That still doesn't make sense.
>
> If you call disable_irq in the IRQ handler you will deadlock because it
> waits until the IRQ handler has completed.
Right, the uio_userirq_handler() function should use
disable_irq_nosync() instead of disable_irq(). Otherwise we'll end up
waiting forever for IRQ_INPROGRESS to be cleared in synchronize_irq()
in the case of CONFIG_SMP.
Thanks!
/ magnus
|  |