Re: gadget file storage with variable maxpacket
David Brownell <[email protected]>
| Newsgroups | gmane.linux.usb.devel |
|---|---|
| Message-ID | <[email protected]> |
On Wednesday 14 November 2007, ilya wrote: > > > this > > > will be neccessary for wireless usb, among many other > > > things. > > > > What other things? > > wireless usb will be introducing a lot of new control requests, flow > control [ie: stalling endpoints should be the last resort because in wusb > you can NAK and the host will wait for a special device notification to send > a transfer token instead of constantly polling as in wired usb], association, > etc. i think a lot of these things could be handled by the controller driver, > but there are a lot of other stuff that could be standardized and handled > by the "gadget" client side. > > what does david brownell think about this? He is curious about this idiom of asking questions in the third person, rather than second person. ;) Most control requests shouldn't require changes to the framework. The NAK stuff seems normal ... if there's no data, nobody should trigger a STALL even today, see how high speed PING works. In terms of changing maxpacket, he's not sure why that would need to be visible to the gadget driver. As he recalls, a special value in the endpoint descriptor signifies variable packet size. And to the extent it's all for bandwidth management, that can (and hence probably *should*) be done in the controller driver ... certainly for bulk transfers, possibly not for periodic transfers (like video/audio, where less bandwidth requires switching to lower-quality encodings). Basically, he'd wait till there's a concrete proposal about any interface changes ... and would be skeptical about any which called for significant framework changes for anything other than ISO data streaming applications. (Of which there are more or less zero in Linux today...) - Dave ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel