Date: Mon, 27 Dec 2004 14:38:39 -0800 From: Julian Elischer <julian@elischer.org> To: hselasky@c2i.net Cc: freebsd-usb@freebsd.org Subject: Re: USB vendore designations.. Message-ID: <41D08EEF.50807@elischer.org> In-Reply-To: <200412271242.43441.hselasky@c2i.net> References: <41CB38A7.5020700@vicor.com> <200412261747.36555.hselasky@c2i.net> <41CFB6AE.1080705@elischer.org> <200412271242.43441.hselasky@c2i.net>
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Hans Petter Selasky wrote: >On Monday 27 December 2004 08:15, Julian Elischer wrote: > > >>Now, when you do the "doobell trick" as descibed in the spec, >>there is one little part of it.. that is the catch. >> >>The spec says: >>"Software should first deactivate all active qTDs, wait for the >>queue head to go inactive, then remove the queue head from >>the asynchronous list." >> >>Note the word "all" >> >>Ok, so since we want to remove only SOME of the qTDs from the queue >>(those corresponding to the aborting command), and we need to read >>the status word to see which has been completed by whether the >>active bit is set, and since we are in a race with the hardware >>to clear the active bit, which of the qTDs, not in the list of >>qTDs we want to remove, was completed? >> >> >> >Maybe the EHCI driver should not reuse the QH's for transfers on the same >pipe, but instead like I did, have one QH for each transfer, insterted into >the asynchronous schedule after that the last QH has been removed? > It's an interesting idea.. where did you do this? In a new driver? sorry to be stupid but qa pointer would be good? s this the driver in _usb I think I saw from you earlier? It has the good point of being "clean" It has the bad point of only allowing one transaction per interrupt cycle. > >Yours >--HPS >_______________________________________________ >freebsd-usb@freebsd.org mailing list >http://lists.freebsd.org/mailman/listinfo/freebsd-usb >To unsubscribe, send any mail to "freebsd-usb-unsubscribe@freebsd.org" > >
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