On Mon, Aug 11, 2014 at 04:16:11PM -0400, Alan Stern wrote: > On Mon, 11 Aug 2014, Michael Grzeschik wrote: > > > Hi Alan, > > > > On Mon, Aug 11, 2014 at 10:28:12AM -0400, Alan Stern wrote: > > > On Mon, 11 Aug 2014, Felipe Balbi wrote: > > > > > > > On Mon, Aug 11, 2014 at 09:44:05AM -0400, Alan Stern wrote: > > > > > On Mon, 11 Aug 2014, Felipe Balbi wrote: > > > > > > > > > > > > > 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? > > > > > > > > > > > > g_uvc needs a userspace counterpart. If we connect to the host before > > > > > > userspace is ready, we might connect as a non-usable function. > > > > > > > > > > Okay, but can't that be fixed in g_uvc? Have it disable the pullup > > > > > until the userspace component is ready, then enable the pullup. > > > > > > > > that might be too late, although propbably not catastrophic. > > > > > > It looks like the UDC core needs to be improved a little. Right now, > > > udc_bind_to_driver() unconditionally calls usb_gadget_connect(), > > > thereby overriding any calls the gadget driver may have made during its > > > bind callback. > > > > > > What we should do instead is call usb_gadget_connect() only if the > > > gadget driver didn't try to change the pullup setting. > > > > > > > I remember last years discussion regarding the usage of > > usb_gadget_deactivate and usb_gadget_activate in composite.c: > > > > http://markmail.org/message/haqte4elxt5xnuf2 > > Okay. I don't really care what approach gets used, so long as the > final version works properly. > No, I don't see this problem has fixed, android kernel simply deletes usb_gadget_connect(udc->gadget) at udc_bind_to_driver https://android.googlesource.com/kernel/common/+/b94f8f691c550d1e07c21d6c672b916377c9d6d4%5E%21/#F0 -- 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
