Hi Oliver, On Tue, Aug 30, 2016 at 11:32:01AM +0200, Oliver Neukum wrote: > On Mon, 2016-08-29 at 15:36 +0300, Heikki Krogerus wrote: > > +What: /sys/class/typec/<port>/current_data_role > > +Date: June 2016 > > +Contact: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx> > > +Description: > > + The current USB data role the port is operating in. > > This > > + attribute can be used for requesting data role > > swapping on the > > + port. Swapping is only supported as an asynchronous > > operation > > + and requires polling of the attribute in order to know > > the > > + result, so successful write operation does not mean > > successful > > + swap. > > + > > That is badly formulated. Does it mean that poll() or select() > can be used or does the value need to be repearedly read? Does polling not always mean poll/select? > And how would you learn about an error? This is what I'm also really worried about. I'm now wondering did I give up too easily on this to Guenter in hope to move this thing forward. He said it's problematic to do these calls synchronously for him. Was it something related to potential conflicting role swaps from both ends? Guenter, can you please elaborate? And how do you plan to report failures with the swaps? Thanks, -- heikki -- 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
