From mboxrd@z Thu Jan  1 00:00:00 1970
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Date: Tue, 29 Nov 2005 14:28:29 +0100
From: Philippe Gerum <rpm@xenomai.org>
MIME-Version: 1.0
Subject: Re: [Xenomai-core] rt_intr_enable() requierd after rt_intr_create
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To: =?ISO-8859-1?Q?Ignacio_Garc=EDa_P=E9rez?= <iggarpe@domain.hid>
Cc: xenomai-core <xenomai@xenomai.org>

Ignacio Garc=EDa P=E9rez wrote:
> Hi,
>=20
> I noticed that when an interrupt object is created using
> rt_intr_create(), it is created disabled, and a call to rt_intr_enable(=
)
> is necessary for the ISR to be called.
>=20
> Question is: is this the expected behaviour?.

Yes. You don't necessarily want to take interrupts immediately after the=20
object is created, for which you might have some additional housekeeping=20
chores to perform before that.

  If so, I think this should
> be mentioned somewhere in the rt_intr_create documentation. In fact,
> from reading the docs one could infer the opposite.
>=20

Ok, will add a note to rt_int_create().

> On a related issue, I noticed that the rt_intr_enable() documentation s=
ays:
>=20
> "Enables the hardware interrupt line associated with an interrupt
> object. Over Adeos-based systems which mask and acknowledge IRQs upon
> receipt, this operation is necessary to revalidate the interrupt channe=
l
> so that more interrupts from the same source can be notified."
>=20
> Is this correct?. I ask because the rt_intr_create() documentation tell=
s
> you to just return RT_INTR_ENABLE from the ISR if you want this. It's
> confusing.
>=20

Well, the text seems pretty clear to me here: rt_intr_enable() specifies=20
that the re-enabling _operation_ should be carried on after IRQ receipt,=20
but not necessarily using rt_intr_enable(). Returning RT_INTR_ENABLE=20
from the ISR is just the other way to do this.

>=20
> Nacho.
>=20
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>=20


--=20

Philippe.