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 S1753460AbcEYNMk (ORCPT <rfc822;w@1wt.eu>);
	Wed, 25 May 2016 09:12:40 -0400
Received: from bh-25.webhostbox.net ([208.91.199.152]:56167 "EHLO
	bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1750812AbcEYNMj (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Wed, 25 May 2016 09:12:39 -0400
Subject: Re: [RFC PATCHv2] usb: USB Type-C Connector Class
To: Heikki Krogerus <heikki.krogerus@linux.intel.com>
References: <1463661894-22820-1-git-send-email-heikki.krogerus@linux.intel.com>
 <57445A31.9060304@roeck-us.net> <20160525113058.GC27570@kuha.fi.intel.com>
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
From: Guenter Roeck <linux@roeck-us.net>
Message-ID: <5745A4A2.9060502@roeck-us.net>
Date: Wed, 25 May 2016 06:12:02 -0700
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101
 Thunderbird/38.7.2
MIME-Version: 1.0
In-Reply-To: <20160525113058.GC27570@kuha.fi.intel.com>
Content-Type: text/plain; charset=windows-1252; format=flowed
Content-Transfer-Encoding: 7bit
X-Authenticated_sender: linux@roeck-us.net
X-OutGoing-Spam-Status: No, score=-1.0
X-AntiAbuse: This header was added to track abuse, please include it with any abuse report
X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net
X-AntiAbuse: Original Domain - vger.kernel.org
X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12]
X-AntiAbuse: Sender Address Domain - roeck-us.net
X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: linux@roeck-us.net
X-Authenticated-Sender: bh-25.webhostbox.net: linux@roeck-us.net
X-Source: 
X-Source-Args: 
X-Source-Dir: 
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 05/25/2016 04:30 AM, Heikki Krogerus wrote:
> 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.
>

I'll send a follow-up patch hopefully later today which fixes all the problems
I have found so far.

Guenter