Re: [PATCH] pci: change msi-x vector to 32bit

H. Peter Anvin
2008-08-18T22:14:34Z

Alan Cox wrote:
>>> I completely agree that irq number 99.9% of the time should be a completely
>>> abstract token.
>> Sure, although one nice reason for doing the abstraction first is that
>> it stops people imposing fragile numbering schemes on irq ...
>
> On a lot of embedded devices IRQ numbers are not abstract and not
> fragile. I'm all for abstracting out interrupts nicely but it isn't just
> the legacy PC cases to consider - a lot of embedded is at least as
> defined, rigid and meaningfully numbered as ISA.
>

Note that James said:

> Sure, but you have 16 (or whatever) legacy interrupts. You still call
> them 1-16 (or ISA-1 through ISA-16). By the time we reach this stage,
> we're essentially doing string table lookups for the interrupts, so
> there's no need to pre-allocate them (except as a possible arch
> implementation detail).

I think the point is that if we're going to have a meaningful name, it
should be a string, so we can impose whatever naming scheme makes sense
for the platform. Even on embedded platforms it may mean that the flat
number scheme isn't what makes sense.

-hpa