On Mon, 11 Aug 2014, Peter Chen wrote: > > Hello Peter, > > > > I have seen this call is still returning EOPNOTSUPP which is also > > returned by usb_gadget_connect and usb_gadget_disconnect if the pullup > > function is not available. Should it not handle that case somehow special? > > > > > > Is it still a valid condition to bailout if vbus is not active? > > > > Hi Michael, > > I did this for possible pullup dp without connection (eg load gadget driver before > vbus connect), it breaks USB spec, see 7.1.7.3 Connect and Disconnect Signaling at USB 2.0 spec. 7.1.7.3 doesn't say anything about enabling the D+ pullup before Vbus is active. The closest it comes is the definition of Delta-t2 (TSIGATT), but that is a _maximum_ time, not a _minimum_ time. What makes you think turning on the pullup when Vbus is off is bad? > I don't know what exactly problem you met, but current pullup dp during loading > gadget driver behavior is not suitable for webcam and android use case even vbus > is there. Why not? What's wrong with it? 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
