Date: Sat, 07 Jul 2001 14:41:13 -0700 From: Mike Smith <msmith@freebsd.org> To: Warner Losh <imp@harmony.village.org> Cc: Makoto MATSUSHITA <matusita@jp.FreeBSD.org>, sos@freebsd.dk, current@FreeBSD.ORG Subject: Re: Problems with ata probing twice. Message-ID: <200107072141.f67LfD702155@mass.dis.org> In-Reply-To: Your message of "Sat, 07 Jul 2001 15:02:26 MDT." <200107072102.f67L2QJ72605@harmony.village.org>
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> : There is absolutely no reason for the ata driver not to simply set
> : RF_SHAREABLE and be done with it. It's up to the driver's parent (isa,
> : pci, etc) to decide whether the interrupt is in fact shareable or not.
> :
> : The ata driver itself can share interrupts just fine, and it should
> : reflect this in its interrupt allocation.
>
> Actually, there is a reason. Ata is special like pcic is special.
> Both of them can have multiple interrupt routing methods. When ata is
> connected directly to the south bridge, it can route ISA interrupts,
> even though it is a pci device. In this case, it is unsafe to share
> interrupts between the ata device and anything else. Even though it
> looks like a pci device, the interrupt routing is ISA.
This just reinforces what I said; shareability has nothing to do with the
driver, and everything to do with where the interrupts come *from*.
> Cardbus bridges in laptops have the same problems. And it is looking
> like we can't just use the pcibios to route the interrupts on some
> older machines so we have to have some way to say "use isa interrupts
> for this device." That's a big pain for cardbus bridges because many
> of them would really like to be pci devices so you can relocate memory
> out of the ISA hole, etc.
There's no reason they can't be PCI devices, but using interrupts from
ISA.
--
... every activity meets with opposition, everyone who acts has his
rivals and unfortunately opponents also. But not because people want
to be opponents, rather because the tasks and relationships force
people to take different points of view. [Dr. Fritz Todt]
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