On Thu, Nov 16, 2000 at 04:03:44PM -0000, eeh@netbsd.org wrote:

 > Huh?  I'll admit that bus_space_barrier lacks some of the 
 > flexibility of the barriers available on some architectures,
 > but a BUS_SPACE_BARRIER_WRITE barrier should be sufficient
 > to ensure the write completes.  If completion of the memory
 > operation is not enough to acknowledge the interrupt, your
 > hardware is broken to the point that it is impossible to 
 > write a driver for it on any machine.

As defined BUS_SPACE_BARRIER_WRITE merely requires that all other writes
complete before the one after the barrier.

-- 
        -- Jason R. Thorpe <thorpej@zembu.com>