Hello, I would like to unsubscribe myself from all freebsd mailing lists. I have sent an unsubscribe to freebsd-hackers-unsubscribe, but did not get any response to verify. Since the admin is on the mailing list, I would appreciate if you can delete my name and/or email me the procedure to follow.
thanks -kamal On 7/3/06, Julian Elischer <[EMAIL PROTECTED]> wrote:
Ian Dowse wrote: >In message <[EMAIL PROTECTED]>, Hans Petter Selasky writes: > > >>But there is one problem, that has been overlooked, and that is High speed >>isochronous transfers, which are not supported by the existing USB system. I >>don't think that the EHCI specification was designed for scatter and gather, >>when you consider this: >> >>8 transfers of 0xC00 bytes has to fit on 7 pages. If this is going to work, >>and I am right, one page has to contain two transfers. (see page 43 of >>ehci-r10.pdf) >> >> > >I haven't looked into the details, but the text in section 3.3.3 >seems to suggest that EHCI is designed to not require physically >contiguous allocations here either, so the same approach of using >bus_dmamap_load() should work: > > This data structure requires the associated data buffer to be > contiguous (relative to virtual memory), but allows the physical > memory pages to be non-contiguous. Seven page pointers are provided > to support the expression of 8 isochronous transfers. The seven > pointers allow for 3 (transactions) * 1024 (maximum packet size) > * 8 (transaction records) (24576 bytes) to be moved with this > data structure, regardless of the alignment offset of the first > page. > > yes, as long as the beffers are contiguous in some virtual space then the maximum number of pages they can need is 7. (they actually fit into 6 but they may start part way through the first page and may therefore overflow into a 7th). >Ian >_______________________________________________ >freebsd-hackers@freebsd.org mailing list >http://lists.freebsd.org/mailman/listinfo/freebsd-hackers >To unsubscribe, send any mail to "[EMAIL PROTECTED] " > > _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[EMAIL PROTECTED]"
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