On Thu, Sep 30, 2010 at 10:04:28PM +0200, Florian Echtler wrote: > > > I've just had a look at a serial protocol with Wireshark. The device > > > uses an FTDI USB chip to connect to the host, so my trace now contains a > > > lot of noise caused by the serial adapter. > > > Can somebody give me a quick hint how I can filter that trace to remove > > > the purely USB-related URBs and get only the serial datastream? > > Just subtract out all the protocol and other non-serial data :) > > Seriously, why not enable debugging in the driver, I think it will show > > the data being sent that way. Otherwise you are going to have to write > > a filter that strips out all of the non-serial data, which is a reverse > > of the existing driver. Probably not that hard, but it would require > > some work. > Unfortunately, debugging mode won't work as the driver is running under > Windows in a VM... I'm fine with writing a filter, I just can't find any > documentation what the FTDI chips actually expect over their bulk pipe. > Although the FTDI website has a lot of docs, none seem to actually > describe the data format used for the bulk transfers. > > >From looking at ftdi_sio.c, there seems to be a 2-byte header which is > just thrown away? Yes, there is a two-byte header for incoming data. It isn't thrown away, but you could do just that if you're not interested in modem or line status (byte 0 and 1, respectively). Outgoing data generally has no header, but some legacy devices use a packet format with a one-byte header. /Johan -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
