Re: [PATCH] xen: clear IRQ_NOAUTOEN and IRQ_NOREQUEST when a VIRQis bound

From: Stefano Stabellini
Date: Tue Apr 30 2013 - 11:02:52 EST

On Mon, 29 Apr 2013, Julien Grall wrote:
> Reset the IRQ_NOAUTOEN and IRQ_NOREQUEST flags that are enabled by
> default on ARM. If IRQ_NOAUTOEN is set, __setup_irq doesn't call
> irq_startup, that is responsible for calling irq_unmask at startup time.
> As a result event channels remain masked.
> The clear is already made in bind_evtchn_to_irq with commit a8636c0 but was
> missing in bind_virq_to_irq.
> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>

As in the original commit, you should point out that this change does
not have any effects on x86 (where IRQ_NOREQUEST and IRQ_NOAUTOEN are
cleared by default).

At this point we might as well do this consistently everywhere we
allocate a new evtchn irq, including pirqs and ipis, even though we don't
actually use them on ARM.

If the call to irq_clear_status_flags can be moved earlier, a good place
for it could be xen_irq_init.

> drivers/xen/events.c | 1 +
> 1 file changed, 1 insertion(+)
> diff --git a/drivers/xen/events.c b/drivers/xen/events.c
> index d8cc812..b0ad226 100644
> --- a/drivers/xen/events.c
> +++ b/drivers/xen/events.c
> @@ -994,6 +994,7 @@ int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
> WARN_ON(info == NULL || info->type != IRQT_VIRQ);
> }
> + irq_clear_status_flags(irq, IRQ_NOREQUEST|IRQ_NOAUTOEN);
> out:
> mutex_unlock(&irq_mapping_update_lock);

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