BOUNCE rtl@rtlinux.org: Approval required: (fwd)

[Der Herr Hofrat <der.herr@hofr.at>]

>From owner-rtl Thu Jun 21 06:29:34 2001
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Date: Thu, 21 Jun 2001 06:20:00 -0600
From: Victor Yodaiken <yodaiken@fsmlabs.com>
To: rtl@fsmlabs.com
Subject: Re: [rtl] how to process shared interrupt?
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On Wed, Jun 20, 2001 at 10:46:04PM -0700, qiao wrote:
> 
> Victor Yodaiken wrote:
> > 
> > My belief is that shared interrupts are not very 
> useful for RT systems - does anyone
> > think otherwise?
> > 
> > If an interrupt is shared between RT and non RT 
> devices, the RT driver must do
> > 
> > catch_interrupt:
> >         examine my device
> >         if interrupt is mine
> >                 do regular handling
> >         else
> >                 pend interrupt for Linux/BSD
> >                 find the interrupting non-RT device
> >                 clear device interrupt
> >                 re-enable interrupts from this source
> 
> How to do this four step?
> is there a function that pass the interrupt to non-RT linux kernel? 

pthread_kill (pthread_linux (),RTL_LINUX_MIN_SIGNAL +i)

sends interrupt "i" to Linux.

> > The key point is that the RT driver needs to look at 
> all non-RT devices
> > in order to clear the interrupt source.
> > This is not too hard, but it seems not very RT.
> 
> I think ,in RT interrupt handler , check if the interrupt is it's own ,
> if not ,pass it to non-RT linux to do other jobs, this will be almost RT.

But now the RT device cannot get an interrupt until a linux handler re-enables the 
interrupt.  This may be acceptable in some cases.

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