On Wed, Dec 02, 2015 at 10:12:26AM -0500, Alan Stern wrote: > On Wed, 2 Dec 2015, Rogan Dawes wrote: > > > Hi folks, > > > > I'm wondering if it is possible/reasonable to try to turn a linux > > device with host and OTG ports into something that looks and acts > > like a USB hub? > > Besides all the other responses you received, here's a short answer to > your first question: No, it's not possible. > > There are several reasons for this. The most compelling is that the > hardware isn't capable of doing what you want. In particular, the > hardware found in USB OTG device controllers will respond only to > packets sent to the controller's own address, whereas a hub needs to > handle packets sent to any of the downstream devices' addresses. > > Other reasons include things like the timing restrictions on > inter-packet delays. In principle it would be possible to do this > using special USB hardware (i.e., integrate a hub into a Linux > computer), but it isn't possible with standard host and OTG ports. > > Alan Stern > Thanks for the explanation, Alan. I'm going to try the USBProxy route suggested by Chris first. I have read the documentation for the USB gadgets (multi, hid, printer, serial), but noted that there seem to be quite a few more gadgets available in the source nowadays. e.g. audio, webcam . Are there any plans to document these at some stage? Also, I saw "dummy_hcd.c", which sounds interesting. Rogan Rogan -- 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
