Am Montag, 22. November 2004 12:45 schrieb Feyd:
> On Sat, 30 Oct 2004 11:07:40 -0400 (EDT)
> Alan Stern <[EMAIL PROTECTED]> wrote:
>
> > On Sat, 30 Oct 2004, Axel Waggershauser wrote:
> >
> > > I have no sufficient knowledge of the whole scatter-gather method but I
> > > thought version 2 (avoiding copy_to/from_user with sg) would exactly be
> > > the way to go. As far as I understand it, any memory block in user-space
> > > may be at most fragmented into single pages so where would be that
> > > problem with "correct packetization" compared to the suggestion from
> > > Duncan of scattering single pages in kernel-space? Is the problem that
> > > the user-space memory block would have to be page aligned?
> >
> > (512-byte alignment would be sufficient.) That is the major part of the
> > problem. Another part is that user-space pages may be located in high
>
> Whould an incorrect alignment/packetization cause a real error or only
> hurt performance?
A real error. Within a transfer you need to use maximum sized packets.
If you don't the transfer will end prematurely. Improper alignment means
short packets (or sending garbage).
Regards
Oliver
-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now.
http://productguide.itmanagersjournal.com/
_______________________________________________
[EMAIL PROTECTED]
To unsubscribe, use the last form field at:
https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
