> I will be adding two new bus_*() functions, as follows:
> 
> int bus_io_subregion __P((bus_chipset_tag_t bc, bus_io_handle_t ioh,
> 	bus_io_size_t offset, bus_io_size_t size, bus_io_handle_t *nioh));
> int bus_mem_subregion __P((bus_chipset_tag_t bc, bus_mem_handle_t memh,
> 	bus_mem_size_t offset, bus_mem_size_t size, bus_mem_handle_t *nmemh));

What is the purpose of the 'int' return value from these functions?

Is this to indicate that implementations can return errors and not
allow access to subregions in this manner?

If it's to indicate that there was a problem, e.g. because 'size' was
inconsistent with the given handle and offset, isn't that a software
bug that should be handled with panic()?



cgd