linux-kernel - Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software Interface

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Message-ID: <1455550218.22176.11.camel@suse.com>
Date:	Mon, 15 Feb 2016 16:30:18 +0100
From:	Oliver Neukum <oneukum@...e.com>
To:	Heikki Krogerus <heikki.krogerus@...ux.intel.com>
Cc:	Greg KH <gregkh@...uxfoundation.org>,
	Felipe Balbi <balbi@...nel.org>,
	Mathias Nyman <mathias.nyman@...ux.intel.com>,
	linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org
Subject: Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software
 Interface

On Thu, 2016-02-11 at 15:50 +0200, Heikki Krogerus wrote:
> Because USB Type-C ports (DRP ones) will select the data role randomly
> when you connect (to an other DRP port). USB Type-C spec defines that
> you can "prefer" host mode, but when both ends prefer host mode, it's
> +-0.

That question has not been answered. It would be awkward for the OS
to find itself in the slave role, which it is ill equipped for. So
the data role should be switched before the new device is announced
to user space. How is that handled?

	Regards
		Oliver