On Sat, 9 Nov 1996 20:26:18 -0500 
 Taras Ivanenko <ivanenko@ctpa03.mit.edu> wrote:

 > As far as I can tell, pmap_extract() returns zero when asked to
 > extract the adress which is already physical, i.e. mapped to
 > itself. In your case internal video is probably mapped to physical I/O
 > address, therefore zero. One solution can be to check the adress
 > itself when pmap_extract() returns zero and you are sure the address
 > is valid.

If that is indeed happening, I would classify it as a bug in
pmap_extract().  The next time I get a chance to build an hp300
kernel, I'll verify this... the past physical page of RAM is mapped
va==pa on the hp300 (for various tasks, such as the MMU trampoline),
and it's easy enough to put a call to pmap_extract() at the end of
configure() :-)

Jason R. Thorpe                                       thorpej@nas.nasa.gov
NASA Ames Research Center                               Home: 408.866.1912
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