Re: 2.5.4, cs46xx snd, and virt_to_bus

[<benh@kernel.crashing.org>]

>Would putting a range check and BUG() in the ISA macros for now help there.
>
>Reminds me - we have a request_mem_region problem to address that is sort
>of related to all this. Right now we reserve mem regions without knowing
>properly about ISA mappings. That means drivers are reserving stuff like
>0xD0000. Unfortunately on some non X86 boxes the ISA hole isnt at 640K-1M
>so it appears we want an  isa_request_mem_region and friends to handle those
>platforms ?
>-

I'd rather provide a function to obtain the base address of the ISA hole,
while would also allow us to
 - Return an error when it doesn't exist (a given kernel may or may not
have it depending on which box it's booted, it can't be a compile time
option)
 - Eventually obtain a per-PCI bus ISA hole (the "legacy one" beeing
defined as bus or with a special constant) so multi domain machines
can use multiple VGA cards (eek eek ;)

With that, at least PPC don't require isa_xxx specific functions/macros
(but I can't tell about other archs).

Ben.