RE: [ACPI] [PATCH] add acpi_interrupt_to_irq

From: Nakajima, Jun <>
Date: 2004-01-24 04:35:38
Not a problem to me :-) So if we remove the #ifdef (i.e. both
CONFIG_IA64 and CONFIG_PCI_USE_VECTOR) there, I think acpi_gsi_to_irq is
reasonable there. For x86 we'll switch to (the old) acpi_irq_to_vector
if CONFIG_PCI_USE_VECTOR is configured, and don't do anything for the
usual case. But I don't expect Len to replace every irq in ACPI with
gsi, though.

BTW, we need to think how we support MSI (and PCI Express) for IPF; we
already posted a PCI Express patch for x86. Today's IRQ abstraction on
IPF might have some advantage for supporting MSI, which is required for
PCI Express.


> -----Original Message-----
> From: Bjorn Helgaas []
> Sent: Friday, January 23, 2004 8:36 AM
> To: Nakajima, Jun;; linux-
> Cc: Brown, Len
> Subject: Re: [ACPI] [PATCH] add acpi_interrupt_to_irq
> On Thursday 22 January 2004 8:36 pm, Nakajima, Jun wrote:
> > > What does "vector" mean?
> > For MSI, vector means the (external) interrupt vector, i.e. the
index in
> > the IDT for MSI on x86. So acpi_irq_to_vector() is correct in that
> > ACPI looks at IRQ or GSI (Global system interrupt) vector (yes, it's
> > confusing). SOMETHING should be irq or gsi, as David suggested.
> >
> > Since MSI does not require IRQ (but external interrupt vector), the
> > we did for x86 was to use the vector to unify IRQ and vector. So
> > request_irq() actually gets the interrupt vector number, instead of
> > That's the reason I preferred acpi_irq_to_vector() in that code with
> > configured.
> Sorry to drag this out even longer...  I promise I'll shut up
> after this :-)
> But this business about request_irq() getting an MSI interrupt vector
> number, not an irq, is just a detail of the MSI and architecture
> implementation.  Surely ACPI should just use the abstract Linux
> interrupt interface (request_irq(), free_irq(), etc), which uses
> the "irq" terminology, and should remain ignorant of whether MSI
> is even present.
> Bjorn

To unsubscribe from this list: send the line "unsubscribe linux-ia64" in
the body of a message to
More majordomo info at
Received on Fri Jan 23 12:36:01 2004

This archive was generated by hypermail 2.1.8 : 2005-08-02 09:20:21 EST