On Fri, May 06, 2016 at 10:01:20AM +0300, Felipe Balbi wrote: > > Hi, > > Peter Chen <hzpeterchen@xxxxxxxxx> writes: > >> "Du, Changbin" <changbin.du@xxxxxxxxx> writes: > >> > Hi, Balbi, > >> > > >> > The step to reproduce this issue is: > >> > 1) connect device to a host and wait its enumeration. > >> > 2) trigger software disconnect by calling function > >> > usb_gadget_disconnect(), which finally call > >> > dwc3_gadget_pullup(false). Do not reconnect device > >> > (I mean no enumeration go on, keep bit Run/Stop 0.). > >> > > >> > At here, gadget driver's disconnect callback should be > >> > Called, right? We has been disconnected. But no, as > >> > You said " not generating disconnect IRQ after you > >> > drop Run/Stop is expected". > >> > > >> > And I am testing on an Android device, Android only > >> > use dwc3_gadget_pullup(false) to issue a soft disconnection. > >> > This confused user that the UI still show usb as connected > >> > State, caused by missing a disconnect event. > >> > >> okay, so I know what this is. This is caused by Android gadget itself > >> not notifying the gadget that a disconnect has happened. Just look at > >> udc-core's soft_connect implementation for the sysfs interface, and > >> you'll see what I mean. > >> > >> This should be fixed at Android gadget itself. The only thing we could > >> do is introduce a new usb_gadget_soft_connect()/disconnect() to wrap the > >> logic so it's easier for Android gadget to use; but even that I'm a > >> little bit reluctant to do because Android should be using our > >> soft_connect interface instead of reimplementing it (wrongly) by its > >> own. > >> > > > > If it is a gadget driver, it can call its disconnect explicitly. > > Another thing is the gadget driver should not call usb_gadget_disconnect > > directly, it should call usb_gadget_deactivate or usb_function_deactivate. > > > > Since currently, calling usb_gadget_disconnect may not do real pull down > > dp, Felipe, will you consider adding gadget_driver->disconnect into > > usb_gadget_disconnect after pull down dp? > > this is the detail that I'm not yet entirely sure is always valid. Would > there ever be a situation where we want to drop pull-ups but not tell > the gadget about it ? Yes, we have. - We have enabled pullup dp default for most of platforms, and for gadget obex and uvc will pull down it since it wants app to control it - Some USB charger detection design may need it for the secondary detection. After checking again for usb_gadget_disconnect and usb_gadget_disconnect, I think there is no possible that the dp is still pulled after we call usb_gadget_disconnect, so we don't need to change anything:) -- Best Regards, Peter Chen -- 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
