> Anyway, looking at the code, I'm wondering if it would actually be
>> better to just eliminate that bounce buffer and, instead just transfer
>> the data directly.  This might leave the buffer in an undefined state, I
>> think, however, that is ok.
> 
> 
> I spent an hour thinking about how to do that (without significantly
> uglifying the code), and decided it was more trouble than I wanted to
> go to.  I agree with you -- the function doesn't require a buffer 
> at all.  Anyone who wants to rewrite the function to that extent
> is more than welcome to by me.  ;-)


How does the attached work-in-progress look as a starting point?  Ran it 
against the testsuite and that came up with a few regressions ..... 
However, it isn't totally broken.

One thing I didn't realize is that I can't trust the alignment of the 
hosts buffer and consequently I can't actually avoid the double buffering.

Andrew