Hi, > -----Original Message----- > From: Laurent Pinchart [mailto:laurent.pinchart@xxxxxxxxxxxxxxxx] > Sent: Thursday, July 26, 2012 3:50 PM > To: balbi@xxxxxx > Cc: Bhupesh SHARMA; linux-usb@xxxxxxxxxxxxxxx > Subject: Re: [RFC] usb: gadget: Ensure correct functionality for > gadgets that wish to 'connect' only when directed by user-space > > On Thursday 26 July 2012 13:11:47 Felipe Balbi wrote: > > On Thu, Jul 26, 2012 at 11:53:57AM +0200, Laurent Pinchart wrote: > > > > Until then, I don't think we have a solution for this problem > which > > > > would work always and, in fact, I don't want to have such a > solution > > > > otherwise we will have to maintain it for the forseeable future. > > > > > > I don't agree with you here. > > > > > > The existing usb_gadget_disconnect() function is documented as > > > > > > * Disables the D+ (or potentially D-) pullup, which the host may > see > > > * as a disconnect (when a VBUS session is active). Not all > systems > > > * support software pullup controls. > > > * > > > * This routine may be used during the gadget driver bind() call to > > > prevent > > > * the peripheral from ever being visible to the USB host, unless > later > > > * usb_gadget_connect() is called. For example, user mode > components may > > > * need to be activated before the system can talk to hosts. > > > > > > In practice this doesn't work, calling usb_gadget_disconnect() > during bind > > > doesn't prevent the device from being visible to the USB host. > That's what > > > I > > Ok, I missed that memo, sorry. To me it's working fine, actually. > What's > > the issue you have with that ? > > I just doesn't work :-) Calling usb_gadget_disconnect() during bind > doesn't > prevent the device from being visible to the USB host. Bhupesh has > analyzed > the problem and submitted this RFC as a possible fix. Yes. Felipe, plz go through the problem description as mentioned in the patch log message which can be seen here: http://permalink.gmane.org/gmane.linux.usb.general/66585 Regards, Bhupesh > > > think should be fixed, until the configfs-based solution is ready. > > > > > > We should of course not add any API to expose ->pullup() to > userspace as > > > an interim solution, as that one would need to be maintained. > > > > correct. > > -- > Regards, > > Laurent Pinchart -- 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
