From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1757832AbcH3JcJ (ORCPT <rfc822;w@1wt.eu>);
        Tue, 30 Aug 2016 05:32:09 -0400
Received: from mx2.suse.de ([195.135.220.15]:52119 "EHLO mx2.suse.de"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1756607AbcH3JcI (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Tue, 30 Aug 2016 05:32:08 -0400
Message-ID: <1472549521.2623.10.camel@suse.com>
Subject: Re: [PATCHv6 1/3] usb: USB Type-C connector class
From: Oliver Neukum <oneukum@suse.com>
To: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Greg KH <gregkh@linuxfoundation.org>,
        Guenter Roeck <linux@roeck-us.net>,
        Vincent Palatin <vpalatin@chromium.org>,
        Bin Gao <bin.gao@linux.intel.com>,
        Felipe Balbi <felipe.balbi@linux.intel.com>,
        linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org
Date: Tue, 30 Aug 2016 11:32:01 +0200
In-Reply-To: <1472474182-43858-2-git-send-email-heikki.krogerus@linux.intel.com>
References: <1472474182-43858-1-git-send-email-heikki.krogerus@linux.intel.com>
         <1472474182-43858-2-git-send-email-heikki.krogerus@linux.intel.com>
Content-Type: text/plain; charset="UTF-8"
X-Mailer: Evolution 3.12.11 
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

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@linux.intel.com>
> +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?
And how would you learn about an error?

	Regards
		Oliver