On Tue, 09 Jun 1998 23:25:15 +0200 
 Stefan Grefen <grefen@hprc.tandem.com> wrote:

 > I aggree, but please with a additional switch. This is helpful for
 > driver development but not for daily use.

The DEBUG option isn't really "for daily use", either...  I guess you
and I disagree on the semantics of the DEBUG option.

 > > 	(2) there may be a performance gain for doing aligned access on
 > > 	    _any_ port, even when it is not strictly necessary.
 > 
 > Not if this is the transfer to the device. It would just introduce a
 > copy of the data for no reason.

That's only because your m_pullup() does a copy; there are other ways of
dealing with the problem.  See the CS8900 that _IS_ in the SUP tree at
src/sys/arch/arm32/isa/if_cs_isa().  Look at csCopyTxFrame(), the last
function in the file.  I agree that my example in the NE2000 driver is
a bad one, and I'm planning on fixing it RSN.  (Needed to dig out an
NE2000 to test with :-)

 > No but I can't use the memory mapped or DMA mode. The chip is soldered on 
 > a PC104 board and the EEPROM tells me that no Memory window or DMA is
 > available.

Hm... for a generic CS8900 driver, sounds like we really want callbacks
to the front-end to do the tx/rx buffer handling, then.

Jason R. Thorpe                                       thorpej@nas.nasa.gov
NASA Ames Research Center                            Home: +1 408 866 1912
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