Re: Tyan Tiger 100 (S1832) IO-APIC Problems

On Wed, 25 Feb 2004 00:35:55 -0600 Russ W. Knize wrote:

| Just in case anyne might be interested, I have been trying to debug this
| issue.  It seems that pirq_find_routing_table() is not locating the
| table in the range it is looking.  I turned on debug trace and added
| some other debug code.  The PIRQ signature is not there in that range at
| all.  Without the table, the router is not identified.  I also tried
| forcing ACPI to be enabled, but that didn't seem to help.

I don't know anything about the Tyan Tiger 100, but the PIRQ table
was an M$ creation for Win 98 or thereabouts.  ACPI interrupt
routing has replaced it on some systems, so I don't find it
surprising that the PIRQ table isn't found.  Of course, I guess
that it could be there and Linux just isn't finding it, wherever
it's hidden.  Tough to say which case it is.

I also don't recall the particular problems that you are having.
Is it IO-APIC problems (as in $Subject), or is it just interrupt
routing in general?  If the latter, perhaps asking your questions
on the Linux ACPI mailing list would lead to some answers for you.
([email protected])

| Whether or not any of this matters in the end is a little unclear to me
| at this point.  I have experience with (c)PCI, but not on x86 hardware. 
| Is there an online resource that explains how the APIC is supposed to
| work in a bit more detail?  There aren't very many comments in the code
| to go on.

There are APIC and IO-APIC datasheets available from Intel and
probably other processor and chipset manufacturers, but they are
sorely lacking in anything similar to a theory of operation.

--
~Randy