Re: [pci] Advice needed!

[gmp216@is9.nyu.edu]

> The second problem are images: all PCI bridges provide two or more images of
> PCI bus address space for local processors (image is defined by base address
> and address mask or block size). This images must be dynamic to allow
> software to do address space mapping as it likes. So the problem is: what if
> two or more immages overlap (some addresses fall into two or more image
> ranges at the same time)? Does this issue have to be resolved in hardware or
> hardware isn't responsible for slopy programming?

I'm not sure where this is in the spec, but I'm pretty sure that overlapping
images is an undefined condition and the hardware does not need to do anything
special. It would be a waste of resources for hardware to detect misprogramming
by a "trusted" piece of software like the BIOS or an operating system kernel.
That is assuming no special processor mode is required to access the memory in
question, such as in system management mode in the Intel IA32 architecture.

---
gmp