On Wed, 20 Dec 2006, Clemens Ladisch wrote: > > > In this case, the driver has to take care to avoid using these > > > interfaces at the same time. > > > > I don't understand this. A USB driver doesn't "use" interfaces; all it > > does is send packets to various endpoints. > > These are audio devices with isochrounous endpoints; the driver "uses" > the interfaces by selecting a non-zero altsetting. (In theory, each > audio interface is an independent audio device.) > > > So for example, if interface 0 and interface 1 both contain endpoint 2-in, > > and your driver submits a request to transfer 64 bytes from that endpoint, > > which interface are you "using"? > > The sample format is determined by the "used" altsetting. (In the case > of the Quattro or OmniStudio, the device would sometimes return data > formatted according to the last selected sample format, or sometimes > 'combine' both sample formats and return garbage.) > > I'm not implying that any of this makes sense, or that anybody should > design such a device. :-)
Can you provide information (either "lsusb -v" output or, more succinctly, the entry from /proc/bus/usb/devices) for such a device? Just out of curiosity... Alan Stern ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
