IRQ routing debugging help

[M. Warner Losh]

In message: <20040105181456.L85414 at carver.gumbysoft.com>
            Doug White <dwhite at gumbysoft.com> writes:
: I have an IBM xSeries 335 system here that seems to be having interrupt
: routing issues. With ACPI enabled the keyboard doesn't work. Without ACPI,
: all is happy.
: 
: I have a boot -v output captured from serial console.
: 
: I'd like to learn how to look into these issues so poor jhb isn't stuck
: doing this all the time. :)
: 
: So whats the next step?

Are you set for fresh goat entrails?  How about Eye of Newt? :-)

The next step is to find the $PIR table.  This will give you one set
of information.  Here's a sample PIR table, the format may be a little
different than what I've presented here:

$PIR table at 0x28126c20 version 1.0
PCI interrupt router at 0:15.8 vendor 0x8086 device 0x1234
PCI-only interrupts [                                     ]
entry bus slot device
 00:  00   00    31  INTB  61  [      3 4 5 6 7   9 10 11 12    14 15]
                     INTD  63  [      3 4 5 6 7   9 10 11 12    14 15]
 01:  02   00    03  INTA  61  [          5                          ]
 02:  00   00    30  INTA  60  [      3 4 5 6 7   9 10 11 12    14 15]
                     INTB  61  [      3 4 5 6 7   9 10 11 12    14 15]
                     INTC  62  [      3 4 5 6 7   9 10 11 12    14 15]
                     INTD  63  [      3 4 5 6 7   9 10 11 12    14 15]
 03:  01   00    00  INTA  60  [      3 4 5 6 7   9 10 11 12    14 15]
 04:  02   00    06  INTA  63  [      3 4 5 6 7   9 10 11 12    14 15]
                     INTB  62  [      3 4 5 6 7   9 10 11 12    14 15]
 05:  08   00    00  INTA  63  [      3 4 5 6 7   9 10 11 12    14 15]
 06:  08   00    01  INTA  63  [      3 4 5 6 7   9 10 11 12    14 15]
 07:  02   00    15  INTA  63  [      3 4 5 6 7   9 10 11 12    14 15]
 08:  02   00    08  INTA  62  [      3 4 5 6 7   9 10 11 12    14 15]
 09:  02   00    12  INTA  62  [      3 4 5 6 7   9 10 11 12    14 15]
Link number ---------------^^

The link number is best thought of as 'wire number'.  As you'd expect,
all the INTx pins with the same link number are wire OR'd together.
This means that if Entry #8's (pci2:8) INTA pin is wired to IRQ 10,
then entry 9's INTA pin is also.

Next, you'll need to find the ACPI table (I don't have one handy since
bootverbose goes nuts with ata1 not finding anything, again and
again).  If you are lucky, they will match and be consistant.
However, if they are consistant, you'll likely not be having problems.

If an interrupt works under non-ACPI, then you can use something like
hw.acpi.pci.link.%d.%d.%d.irq to route it.  First %d busno, then %d
slot and the last %d is pin.  A is 0, B is 1, etc.  If non-ACPI works,
then you you can power through things by doing something like

	hw.acpi.pci.link.2.12.0.irq=11
	hw.acpi.pci.link.2.15.0.irq=5

Warner