On Wed, 30 Apr 2014, Felipe Balbi wrote: > > We still have unsolved problem with deferred probe in UDC drivers, so > > there is real need for some fixes. > > sure, we do need a fix, but it's very difficult to know when we can > allow for gadget drivers to be loaded. Think of it this way: > > say you have a system with a single UDC controller, and we allow for > gadget driver probe deferral. First gadget driver you load binds to the > UDC, second gadget driver you load will defer forever, but will still > "probe" (in a sense). lsmod will show two gadget drivers. > > Now say you want to use that gadget driver which is deferred, you unload > first gadget driver and then nothing happens because you have no way to > tell that gadget driver that you want it to bind to the UDC which is now > available. > > see the problem ?
This is the sort of thing that could be fixed by creating a "gadget" bus type. The user would be able to force a gadget to bind to a UDC by writing to the appropriate sysfs file. Of course, I suppose you could always implement the same sort of functionality with a special-purpose sysfs file, without going to all the effort of adding a new bus type. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
