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Date:      Wed, 08 Sep 1999 01:13:56 +0800
From:      Peter Wemm <peter@netplex.com.au>
To:        nate@mt.sri.com (Nate Williams)
Cc:        bde@freebsd.org, "Matthew N. Dodd" <winter@jurai.net>, Warner Losh <imp@village.org>, Warren Welch <wwlists@intraceptives.com.au>, Kevin Day <toasty@dragondata.com>, Ugen Antsilevitch <ugen@xonix.com>, hackers@FreeBSD.ORG
Subject:   Re: PCI modems do not work??? 
Message-ID:  <19990907171356.3280E1CA8@overcee.netplex.com.au>
In-Reply-To: Your message of "Tue, 07 Sep 1999 10:03:26 CST." <199909071603.KAA21766@mt.sri.com> 

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Nate Williams wrote:
> > "Matthew N. Dodd" wrote:
> > > On Sun, 5 Sep 1999, Warner Losh wrote:
> > > > Might be a good time have a sys/dev/sio and have pccard, cardbus, pci
> > > > and isa attachments there.  Yes, I did say cardbus, since I have seen
> > > > cardbus PCI modems that are NOT winmodems.
> > > 
> > > And MCA and EISA attachments.
> > 
> > Well, it seems Bruce objects to this..  I don't know why though.  If he's
> > concerned about loosing the tightly integrated sio<->isa stuff then I guess
> > there could be an "osio" (old sio) or "isasio" or something driver that
> > remains isa-specific.  I could well imagine this could be important for
> > older/slower machines.

[full quote restored for bde's benefit, he may not be reading this thread
 about adding support for this in -hackers]

> My guess is that he's worried that we'll end up with lots of additional
> 'indirection' through the system, thus slowing down the ability to
> service interrupts in a quick manner.

If that's what he's worried about then I wish he'd say so.  Nothing that
we want to do requires breaking this.

> Also, don't fast interrupts depend on the ISA bus?  Fast interrupts are
> a requirement for *any* machine to run at a reasonable speed, old/slow
> or new/fast, it doesn't make any difference.

Yes..  Which is part of the reason for moving the interrupt *setup* to
bus-specific code.  The handler would be the same regardless and there
wouldn't need to be any indirections or performance impairments as a
result.

One of the things I was going to fix was the hack where com_addr() is using
device_get_softc().  This is not fast interrupt safe and needs to go back
to something along the lines of what it was before.  The end result would
be that there would be *less* new-bus code in the core sio.c as it'd be
moved aside.

> Nate

Cheers,
-Peter



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