On Thu, 26 Jan 2012, Oliver Neukum wrote: > Second, it seems to me that in the long run, this is asking for trouble. > IMHO the function should be represented in the device tree between > the device and the interfaces. We have the same constraints as for > interfaces and devices. A function's interfaces cannot do PM independently > and suspending a device means suspending all its functions. This will require a significant amount of change to the entire USB stack. There must be lots of places where we assume that the device is the parent of the interface. (It wouldn't be surprising if userspace makes that assumption as well.) Making it even more difficult is the fact that USB-2 devices don't have functions whereas USB-3 devices do. > We'd get the handling of multifunction devices for free putting functions > into the device tree. Yes, but adding functions to the driver model is far from free. I'm not saying we shouldn't do it eventually, but it will be quite a big job. Alan Stern -- 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
