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Date:      Thu, 12 Dec 1996 11:38:46 -0700
From:      Steve Passe <smp@csn.net>
To:        Peter Wemm <peter@spinner.dialix.com>
Cc:        freebsd-smp@freefall.freebsd.org
Subject:   Re: cvs commit: sys/i386/isa isa.c isa_device.h sio.c 
Message-ID:  <199612121838.LAA02012@clem.systemsix.com>
In-Reply-To: Your message of "Thu, 12 Dec 1996 23:02:58 %2B0800." <199612121502.XAA03371@spinner.DIALix.COM> 

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Hi,
> Steve Passe wrote:
> > fsmp        96/12/12 01:53:03
> > 
> >   Modified:    i386/isa  isa.c isa_device.h sio.c
> >   Log:
> >   created icu_irq_pending(), a function which examines the 8259 IRQ pending
> >   bits.  this is needed by some device probes during boot, when the IO APIC
> >   is being used for actual INTerrupt service.
> >   
> >   code sio.c to use icu_irq_pending() during probe.
> 
> Umm, silly question I guess, but does this code take LOWPRI delivery mode
> into account?  If you're looking on the local apic, you won't see the
> pending interrupt if it's been sent to a different cpu....  But I guess this
> should be fine during boot though.  (no, I've not read the code, I've just

its just for boot.  the sio is presumming all INTs
are masked, then tickles the sio in a way that it expects to see a pending
INT.  no harm in letting it do that, it appears to work fine.  the IO APIC
isn't ready for use at this point, and because of all the complexity of
the APIC exchanges it wouldn't make sense to use them for this anyways.


--
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smp@csn.net	|            FreeBSD




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