On 20/04/15 16:56, Alan Stern wrote: > On Mon, 20 Apr 2015, Roger Quadros wrote: > >>> I don't understand this. Why do you want to defer the add/remove if >>> the device is OTG? Don't host controller drivers expect these things >>> to execute synchronously? >> >> Sorry for the wrong information. We actually defer only the add as the >> OTG state machine might not yet be in Host ready mode. >> The remove is always synchronous and we ensure that the HCD is removed >> when usb_otg_unregister_hcd() returns. > > That's okay then, but it does leave one potential hole. What happens > if usb_add_hcd() is deferred for so long that usb_remove_hcd() gets > called before the add can complete? We keep track of the HCD state in the OTG state machine and if it was not yet added then _usb_remove_hcd() is not called during usb_otg_unregister_hcd() in the usb_remove_hcd() call. cheers, -roger -- 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
