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 S932126AbcEYLbG (ORCPT <rfc822;w@1wt.eu>);
	Wed, 25 May 2016 07:31:06 -0400
Received: from mga04.intel.com ([192.55.52.120]:58001 "EHLO mga04.intel.com"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1751043AbcEYLbE (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Wed, 25 May 2016 07:31:04 -0400
X-ExtLoop1: 1
X-IronPort-AV: E=Sophos;i="5.26,364,1459839600"; 
   d="scan'208";a="110197854"
Date: Wed, 25 May 2016 14:30:58 +0300
From: Heikki Krogerus <heikki.krogerus@linux.intel.com>
To: Guenter Roeck <linux@roeck-us.net>
Cc: Greg KH <gregkh@linuxfoundation.org>,
        Mathias Nyman <mathias.nyman@linux.intel.com>,
        Felipe Balbi <felipe.balbi@linux.intel.com>,
        Oliver Neukum <oneukum@suse.com>,
        Rajaram R <rajaram.officemail@gmail.com>,
        Andy Shevchenko <andy.shevchenko@gmail.com>,
        linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org
Subject: Re: [RFC PATCHv2] usb: USB Type-C Connector Class
Message-ID: <20160525113058.GC27570@kuha.fi.intel.com>
References: <1463661894-22820-1-git-send-email-heikki.krogerus@linux.intel.com>
 <57445A31.9060304@roeck-us.net>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <57445A31.9060304@roeck-us.net>
User-Agent: Mutt/1.6.1 (2016-04-27)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Hi,

On Tue, May 24, 2016 at 06:42:09AM -0700, Guenter Roeck wrote:
> > +struct typec_capability {
> > +	enum typec_data_role	role;
> > +	unsigned int		usb_pd:1;
> > +	struct typec_altmode	*alt_modes;
> > +	unsigned int		audio_accessory:1;
> > +	unsigned int		debug_accessory:1;
> > +
> > +	int			(*fix_role)(struct typec_port *,
> > +					    enum typec_data_role);
> > +
> > +	int			(*dr_swap)(struct typec_port *);
> > +	int			(*pr_swap)(struct typec_port *);
> > +	int			(*vconn_swap)(struct typec_port *);
> > +
> 
> The function parameter in those calls is all but useless to the caller.
> It needs to store the typec_port returned from typec_register(), create a
> list of ports, and then search through this list each time one of the
> functions is called. This is quite expensive for no good reason.
> 
> Previously, with typec_port exported, the called code could use the stored
> caps pointer to map to its internal data structures. This is no longer
> possible.

True, the API now is in practice broken.

> I think it would be useful to provide a better means for the called function
> to identify its context. Maybe provide a pointer to the private data in
> the registration function and use it as parameter in the callback functions ?

Sounds reasonable.


Thanks,

-- 
heikki