Hedde Bosman wrote: > I've owned a MIDEX8 for some years now and am now attempting a driver > for it. [...] > it looks a bit like the standard usb midi class, but it requires some > periodic (i guess timer) messages on endpoint 0x02 Why "requires"? What happens if you do not send them? > Not all (interrupt) urbs that are submitted will complete (within 25 > ms at least). And why would that be a problem? > Sometimes after sending a few messages, an empty urb shows up in > wireshark. However, in code, there's an if-statement that should allow > only messages of length > 0 to be submitted (line 568, if (num_read > > 0)). Try adding a check before the actual usb_submit_urb() call, but nothing would protect against your code accidentally changing the transfer_buffer_length of an active URB field later. > Might this have to do with issue 1? Not unless you have mixed up input and output URBs. Regards, Clemens _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
