On Sun, May 02, 2004 at 07:19:11PM +0300, Jukka Marin wrote:
> On Sun, May 02, 2004 at 06:11:15PM +0200, Manuel Bouyer wrote:
> > It needs N contigous pages. In theory you can have Ram/N allocated and
> > have it still fail, if the memory fragmentation is at its maximum.
> > I think this can be worked around by bumping a kernel parameter,
> > but I don't remember which one :(
> 
> Why does it need such a big buffer?  For maximum performance, sure, but..
> (Well, I guess using anything more than one page would potentially cause
> the same problem..)

I think it's a hardware issue: the USB controller reading only contigous
pages, or something like it.
Based on this , the buffer size may be 64k, or 64k + 1 page. But it's only
a guess, I didn't look at the code.

-- 
Manuel Bouyer <bouyer@antioche.eu.org>
     NetBSD: 26 ans d'experience feront toujours la difference
--