Hi Phil, Every DisplayLink device should have a unique USB PID/serial number combo. So you'd need both in your id string, but then that sounds like a good strategy for uniquely identifying a particular device. Thanks for raising this issue of ownership of devices between drivers and apps! libdlo doesn't really try to deal with this system-wide yet. Also very interested in hearing how precedents might guide us. It may be these type of devices are somewhat unique in that they're, in a sense, mostly stateless. Just screens to scribble on. Assuming we want to allow for uses other than through X, we do need to have some concepts of current ownership and end-user intent about the purposes they want a screen to be dedicated to. But also don't want to make this too complex, as most people probably will be using through X eventually. Thanks again, Bernie <div class="gmail_quote">On Sat, May 23, 2009 at 7:50 AM, Phil Endecott <<a href="mailto:spam_from_libdlo@chezphil.org">spam_from_libdlo@chezphil.org</a>> wrote: <blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> This leaves the question of how to name the displays. We can see serial numbers in the dlo_devinfo_t; is this really a unique number? I.e. do the devices have PROMs in them? I've dismantled my dongle and it does indeed have an I2C PROM, but is this essential to the design or is it the first thing that el cheapo OEM will not implement? (I have seen other USB devices that present a default set of IDs if no PROM is attached.) I'm trying to think of precedents, but I can only think of things where the kernel and udev choose names; that doesn't apply to libusb stuff. What else uses libusb? How does SANE name devices? </blockquote></div>