Alan, thanks for your reply.
On 02.01.2005 05:05, Alan Stern wrote: > Which host controller driver are you using? On my own test machines, uhci_hcd. So far I am under the impression that every installation produces those errors but I don't have positive knowledge about an installation not using uhci_hcd. > In general, a non-running isochronous pipe shouldn't generate CRC errors. >From past discussions on this list, I get the impression that -EILSEQ can also signal a timeout condition. > For an IN transfer you could expect to see -EPROTO, but various host > controllers and drivers might report the error differently. For an OUT > transfer there shouldn't be any errors at all. Indeed, the -EILSEQ errors come from the IN transfers. The OUT transfers are better behaved. > Isochronous pipes don't stall (I think -- the spec is ambiguous). In fact > they don't have any handshaking capability at all. Well, the manufacturer's interface documentation (although I have learned not to take it too literally) explicitly warns that the isochronous pipes have always to be fed so that the data stream doesn't break, because otherwise the pipe would return an error on every subsequent operation until it was reset. Sounds like stalling to me, although they never mention the word. > It sounds like you're doing things right. Maybe the device is > deliberately generating bad CRCs? Would a self-respecting USB device do something like that? ;-) Anyway, the interface docs don't mention anything of that sort, but after working on this device for a year nothing surprises me much anymore. How could I find out? Regards Tilman -- Tilman Schmidt E-Mail: [EMAIL PROTECTED] Bonn, Germany Steinbach's Guideline for Systems Programming: Never test for an error condition you don't know how to handle. ------------------------------------------------------- The SF.Net email is sponsored by: Beat the post-holiday blues Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek. It's fun and FREE -- well, almost....http://www.thinkgeek.com/sfshirt _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
