Date: Fri, 02 Jan 2004 16:30:44 -0500 (EST) From: John Baldwin <jhb@FreeBSD.org> To: ticso@cicely.de Cc: current@FreeBSD.org Subject: Re: Still IRQ routing problems with bridged devices. Message-ID: <XFMail.20040102163044.jhb@FreeBSD.org> In-Reply-To: <20040102195244.GE17023@cicely12.cicely.de>
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On 02-Jan-2004 Bernd Walter wrote:
> On Fri, Jan 02, 2004 at 02:19:53PM -0500, John Baldwin wrote:
>>
>> On 01-Jan-2004 Bernd Walter wrote:
>> > On Thu, Jan 01, 2004 at 10:12:23AM -0700, M. Warner Losh wrote:
>> >> In message: <20040101155100.GF11668@cicely12.cicely.de>
>> >> Bernd Walter <ticso@cicely12.cicely.de> writes:
>> >> : On Wed, Dec 31, 2003 at 10:22:30PM -0700, M. Warner Losh wrote:
>> >> : > In message: <20040101013224.GC11668@cicely12.cicely.de>
>> >> : > Bernd Walter <ticso@cicely12.cicely.de> writes:
>> >> : > : The board is an old Asus T2P4 with 3 bridged cards and $PIR table.
>> >> : > : All IRQs behind bridges get bogusly IRQ4 instead of the right ones.
>> >> : > : Is this only a problem on some boards or do we have a general irq
>> >> : > : routing problem with bridges?
>> >> : >
>> >> : > It is a problem with some bridges and PCI BIOS interrupt routing.
>> >> :
>> >> : The intline registers are correct - that's what used to run since years.
>> >> : What has the kind of bridge to do with it?
>> >>
>> >> just what the code does :-)
>> >
>> > But bridges are handled generic so why would only some bridges show
>> > this problem?
>> > The bridges are 21050 types btw.
>>
>> Sounds like a BIOS bug. If a bridge isn't listed in the $PIR, we
>> use the barber-pole swizzle to route across it. However, that is
>
> It can't know about my bridges because all of them are on cards and
> they wouldn't won't fit with just 7 entries.
Ok, if they are on cards, that is correct.
>> technically only defined for bridges on add-in cards. The only
>> way we can tell if a bridge is on an add-in card is if it is not
>> listed either in ACPI's namespace with a _PRT or it is not listed
>> in the $PIR. Part of teh problem is that we shouldn't be using
>
> It's not that simple.
> The chips behind the bridges are layed out to all use INTA on the
> primary bus, but INTA is correctly routed for non-bridged cards.
> I have no clue about $PIR and therefor have no idea where irq4 comes
> from - any pointer to $PIR documents are welcome.
Erm, according to the PCI spec, the devices behind the bridges on the
add-in cards will swizzle their interrupts. Thus, device 8.0 will
use INTA on the add-in card's connect, 9.0 will use INTB for its
INTA, etc. We use the $PIR to then figure out what IRQ to use for
INT[ABCD] on that slot as appropriate. Thus, it would work something
like this:
1) device 1.8.0 wants to route INTA so it asks the bridge for the IRQ
2) the bridges translates that into INTA on itself, and asks its parent
for a route to INTA at its slot (say 0.2.0).
3) the host bridge lookes up 0.2.0 INTA in the $PIR, chooses an IRQ from
the possible list (defaults to just using first IRQ) and returns it.
This step should be skipping IRQ 4 adn using IRQ 10 or 11 instead
For device 1.9.0, the bridge translates that into 0.2.0 INTB. Hope that
makes sense.
--
John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve!" - http://www.FreeBSD.org/
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