From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934166AbcBQKaL (ORCPT ); Wed, 17 Feb 2016 05:30:11 -0500 Received: from mail-pf0-f175.google.com ([209.85.192.175]:34315 "EHLO mail-pf0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933935AbcBQKaH (ORCPT ); Wed, 17 Feb 2016 05:30:07 -0500 From: Felipe Balbi X-Google-Original-From: Felipe Balbi To: Oliver Neukum , Heikki Krogerus Cc: Felipe Balbi , Mathias Nyman , Greg KH , linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org Subject: Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software Interface In-Reply-To: <1455699834.7626.4.camel@suse.com> References: <1455037283-106479-1-git-send-email-heikki.krogerus@linux.intel.com> <1455037283-106479-3-git-send-email-heikki.krogerus@linux.intel.com> <20160209182155.GC31787@kroah.com> <20160210103042.GB5270@kuha.fi.intel.com> <20160210172035.GA28335@kroah.com> <20160211135011.GA32213@kuha.fi.intel.com> <1455550218.22176.11.camel@suse.com> <20160216092238.GA18565@kuha.fi.intel.com> <1455629987.4532.25.camel@suse.com> <20160217075841.GA24649@kuha.fi.intel.com> <1455699834.7626.4.camel@suse.com> User-Agent: Notmuch/0.21 (http://notmuchmail.org) Emacs/25.0.50.2 (x86_64-pc-linux-gnu) Date: Wed, 17 Feb 2016 12:29:55 +0200 Message-ID: <87fuwrsk7w.fsf@ti.com> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha1; protocol="application/pgp-signature" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-=-= Content-Type: text/plain Content-Transfer-Encoding: quoted-printable Hi, Oliver Neukum writes: > On Wed, 2016-02-17 at 09:58 +0200, Heikki Krogerus wrote: >> On Tue, Feb 16, 2016 at 02:39:47PM +0100, Oliver Neukum wrote: >> > On Tue, 2016-02-16 at 11:22 +0200, Heikki Krogerus wrote: >> > > > 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? >> > >=20 >> > > In the class driver, once we add support for preselecting the role, >> > > when the connection happens we compare the initial role to the >> > > preselected one and execute swap if it differs. Only after that we >> > > notify userspace. >> >=20 >> > Yes, but we need an API. We can't keep adding to it. So if that >> > is to be supported, it needs to be defined now. >>=20 >> When you say API, do you mean the API the class provides to the >> drivers? Or did you mean ABI which would be the sysfs in this case? > > The API to user space. That is the point. We cannot break user space. > Once this sysfs API is upstream we are stuck with it. yeah, in fact I have been wondering if sysfs is the best interface to userspace. I talked with Heikki a few days back about this; I was wondering if something like what the NFC folks did with netlink would be better here. =2D-=20 balbi --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJWxEukAAoJEIaOsuA1yqREuo8P/jTbINFcgWGiS5ykpDXlyPUD MiynfZN2xD5ne0IAeefdIlaffq7BBCFT9AssSjADx89UI8Y5afe5TaymBKwzx8KG mDPDVTIXDkVMhVq4ZdI7GnoW17SNrDEyxduuQgPcqp4UVS9zBQ8r7Xcm5+OmTvy7 FijkkCa6QFCrjBAgR0w3Ds4wkRvBwAYX2Ad+bpsf0bAgtmX6TEAG0S62DOjdr+5q NO4W+hWtUXhQObEYjHjDkx5R6C6tK5YxCHC+POc2aHdxI4bn+LCpIcjwGqt0XOvk Tc7NDBM7Ra+Emq6KvKYieiw75xVMfjTS6LyqaRIm0iZEu0LYePv8T0OLIXoUTt1a iW10g7/8Faz0Bl2FSQ9DEPSmuC0lrdTJ1Y+PvCL1VwQSUKG9yscuIMF1i6oMr8Qq 1+w8t4KLmg7sNPEEN4pMmk/Mam5dfhkVClv6A46OzPRW7hY55dkLAhaq2ajtdlXw nMFhFLFqhp0q7ysluchtynF9keBAPFijoMHXLRn5IdhBppGi6EgHFvAO+kzhZMZ7 eKeC8HDTwAOIGxWD8CAMuVGpHpWdmcfoe42jXi4lRZAVP9Ycd820qiKo7P9blPS/ cPYY9cFek/usg/BJa2LAdowk7FhzCcS9U+zkPk1ZWTtJGt7zMR7KALCTGT8x9LDI UQfs1BHT8icn4Da5PMPA =dHT+ -----END PGP SIGNATURE----- --=-=-=--