Re: PCI IRQ problems -- update

Jim Paris
2004-12-11T20:02:55Z

> The PIIX should be in legacy mode by default in which case it would be
> on IRQ 14/15 only. Can you post boot messages ?

Sure. This is with the PIIX interrupt rerouted to IRQ 5:
https://jim.sh/svn/jim/devl/toughbook/log/irq5
Portions of note:

Linux version 2.6.10-rc3 (jim@hypnosis) (gcc version 3.3.4 (Debian 1:3.3.4-13)) #6 Sat Dec 11 11:33:57 EST 2004
...
PCI: Probing PCI hardware (bus 00)
PCI: Ignoring BAR0-1 of IDE controller 0000:00:1f.1
...
Uniform Multi-Platform E-IDE driver Revision: 7.00alpha2
ide: Assuming 33MHz system bus speed for PIO modes; override with idebus=xx
ICH3M: IDE controller at PCI slot 0000:00:1f.1
PCI: Enabling device 0000:00:1f.1 (0005 -> 0007)
ACPI: PCI Interrupt Link [LNKC] enabled at IRQ 5
PCI: setting IRQ 5 as level-triggered
ACPI: PCI interrupt 0000:00:1f.1[A] -> GSI 5 (level, low) -> IRQ 5
ICH3M: chipset revision 2
ICH3M: not 100% native mode: will probe irqs later
ide0: BM-DMA at 0x1840-0x1847, BIOS settings: hda:DMA, hdb:pio
Probing IDE interface ide0...

> > I'm not sure how to get to the root cause of the problem, though. For
> > starters: where _should_ the INTA of the IDE card go, if anywhere? If
>
> Quite possibly nowhere. IDE controllers have two modes one in which they
> are normal PCI devices (and use INTA) and one in which they are "legacy"
> compatible and use IRQ14/15 directly so they work with pre-PCI operating
> systems.

OK, I see. Does Linux leave it in legacy mode even when using a
specific driver like piix? Do you know how I can get more information
on the state of it at boot, to see if BIOS did leave it in legacy
mode?

-jim