Documentation/i386/IO-APIC.txt (Re: 2.6.11 USB broken on VIAcomputer (not just ACPI))

[Xavier Bestel]

Le mardi 15 mars 2005 Ã 21:54 -0800, Andrew Morton a Ãcrit :
> You may be able to set the thing up by hand with the help of
> Documentation/i386/IO-APIC.txt.

There's something I don't get in this document's ascii-art:

8<------------------------------------------------------------------
               ,-.        ,-.        ,-.        ,-.        ,-.
     PIRQ4 ----| |-.    ,-| |-.    ,-| |-.    ,-| |--------| |
               |S|  \  /  |S|  \  /  |S|  \  /  |S|        |S|
     PIRQ3 ----|l|-. `/---|l|-. `/---|l|-. `/---|l|--------|l|
               |o|  \/    |o|  \/    |o|  \/    |o|        |o|
     PIRQ2 ----|t|-./`----|t|-./`----|t|-./`----|t|--------|t|
               |1| /\     |2| /\     |3| /\     |4|        |5|
     PIRQ1 ----| |-  `----| |-  `----| |-  `----| |--------| |
               `-'        `-'        `-'        `-'        `-'

every PCI card emits a PCI IRQ, which can be INTA,INTB,INTC,INTD:

                               ,-.
                         INTD--| |
                               |S|
                         INTC--|l|
                               |o|
                         INTB--|t|
                               |x|
                         INTA--| |
                               `-'

These INTA-D PCI IRQs are always 'local to the card', their real meaning
depends on which slot they are in. If you look at the daisy chaining diagram,
a card in slot4, issuing INTA IRQ, it will end up as a signal on PIRQ2 of
the PCI chipset. [...]
8<------------------------------------------------------------------

If I follow the wire from Slot4's INTA, I'm ending on PIRQ4 whereas the
doc says IRQ2. Do I need glasses, or a new fixed-font ?

	Xav


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