[Xenomai-help] Defensive IRQ allocation procedure.

[Xenomai-help] Defensive IRQ allocation procedure.

[Martin Shepherd]

Am I correct in believing that an RTDM driver can safely call
request_irq() from its non-realtime ioctl_nr() callback? I want to do
this to verify that a non-realtime driver isn't using the same IRQ as
my realtime device, before I attempt to use it in my RTDM driver, and
as well as to prevent any non-realtime drivers from allocating that
IRQ once I have started to use it. I can't do this at module
initialization time, because I don't know which of our identical
digital I/O boards is connected to what, until I perform I/O to them,
and not all of them need interrupts.

Thanks,

Martin

Re: [Xenomai-help] Defensive IRQ allocation procedure.

[Gilles Chanteperdrix]

Martin Shepherd wrote:
> Am I correct in believing that an RTDM driver can safely call
> request_irq() from its non-realtime ioctl_nr() callback? I want to do
> this to verify that a non-realtime driver isn't using the same IRQ as
> my realtime device, before I attempt to use it in my RTDM driver, and
> as well as to prevent any non-realtime drivers from allocating that
> IRQ once I have started to use it. I can't do this at module
> initialization time, because I don't know which of our identical
> digital I/O boards is connected to what, until I perform I/O to them,
> and not all of them need interrupts.

Yes, this should work. Note however, that request_irq will work even if
there is another irq handler registered with IRQF_SHARED, and you pass
IRQF_SHARED too.

-- 
					    Gilles.