cgd@netbsd.org said:
> better way of putting it: DO NOT use BUS_SPACE_MAP_LINEAR, unless you
> have absolutely no other choice. 

OK, I've changed the wording in my text, will send it out
the next time someone offers to port a network driver:-)

But since we have the .._LINEAR option, may it be for
framebuffers only, we should provide a method to make
a pointer from a tag/handle pair. (Which should fail
for handles obtained w/o .._LINEAR.)

First cut:
caddr_t bus_space_vaddr(bus_space_tag_t, bus_space_handle_t);
NULL on error.

best regards
Matthias