Jonathan Perkin scripsit:

>> What do you need exactly? I mean, you want to alter the mapping or
>> just retrieve and access the already existing mapping?
> The latter (and, of course, detect if it's not already mapped and do
> the bus_space_map ourselves).

Hmmm... Interesting. I've been cranking up lately that radeonfb driver 
and I got some interest in those bus_mapping and pmap things. If I 
understand what your problem is, you can't map and remap the same space. 
That make sense. If you don't want to touch the agp driver, frankly I 
can't figure out how you can manage to get access bypassing it. On the 
other hand, we may imagine that the agp drivers either publishes the tag 
it gets with bus_space_map, or that it calculates with bus_space_vmap 
the corresponding virtual address range and publishes it through a 
special function.

Vincent