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SubjectRe: Interrupt sharing
Date

----- Original Message -----
From: "Jeff Garzik" <jgarzik@mandrakesoft.mandrakesoft.com>
To: "Mahadev K Cholachagudda" <mahadev_kc@yahoo.com>
Cc: <linux-kernel@vger.kernel.org>
Sent: Monday, September 25, 2000 7:00 PM
Subject: Re: Interrupt sharing

>
>
> On Mon, 25 Sep 2000, Mahadev K Cholachagudda wrote:
>
> > Hello to all,
> >
> > I have one doubt and is as below.
> >
> >
> > Suppose say the two drivers driver1 and driver2 will install the ISR for
a
> > particular interrupt, say UART0.
> > After some time the interrupt is generated. At this moment, which
driver's
> > ISR is going to execute ?.
> >
> > If driver1 ISR is get executed, will the driver2's ISR is going to
execute
> > ?. If say driver2's ISR is going to execute, Is the data that interrupt
> > generated is going to be emulated to the driver2's ISR.
>
> When an interrupt is delivered, the kernel calls ALL interrupt handlers
> registered for that interrupt. That means all drivers capable of
> sharing interrupts should, ideally, have code in their interrupt handler
> to exit ASAP if no work is necessary.
>
> status = RTL_R16(IntrStatus);
> /* exit ASAP if no interrupt conditions (0), or
> * if the hardware was unplugged (0xFFFF)
> */
> if ((status == 0) || (status == 0xFFFF))
> return;
>

If this is the case, if i am not wrong the data which is to be delivered to
the ISR will be emulated to the each drivers ISR. Is it true ?




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