Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754887AbaKXTM2 (ORCPT ); Mon, 24 Nov 2014 14:12:28 -0500 Received: from sauhun.de ([89.238.76.85]:53717 "EHLO pokefinder.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754074AbaKXTMZ (ORCPT ); Mon, 24 Nov 2014 14:12:25 -0500 Date: Mon, 24 Nov 2014 20:13:47 +0100 From: Wolfram Sang To: Felipe Balbi Cc: Kevin Hilman , Alexander Kochetkov , Tony Lindgren , linux-omap , linux-i2c@vger.kernel.org, lkml Subject: Re: [PATCH v3 2/4] i2c: omap: implement workaround for handling invalid BB-bit values Message-ID: <20141124191347.GA26751@katana> References: <1416518925-20679-1-git-send-email-al.kochet@gmail.com> <1416685634-5864-1-git-send-email-al.kochet@gmail.com> <1416685634-5864-3-git-send-email-al.kochet@gmail.com> <20141124191023.GG25712@saruman> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="X1bOJ3K7DJ5YkBrT" Content-Disposition: inline In-Reply-To: <20141124191023.GG25712@saruman> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --X1bOJ3K7DJ5YkBrT Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Nov 24, 2014 at 01:10:23PM -0600, Felipe Balbi wrote: > On Mon, Nov 24, 2014 at 11:08:48AM -0800, Kevin Hilman wrote: > > On Sat, Nov 22, 2014 at 11:47 AM, Alexander Kochetkov > > wrote: > > > In a multimaster environment, after IP software reset, BB-bit value d= oesn't > > > correspond to the current bus state. It may happen what BB-bit will b= e 0, > > > while the bus is busy due to another I2C master activity. > > > > > > Any transfer started when BB=3D0 and bus is busy wouldn't be complete= d by IP > > > and results in controller timeout. More over, in some cases IP could > > > interrupt another master's transfer and corrupt data on wire. > > > > > > The commit implement method allowing to prevent IP from entering into > > > "controller timeout" state and from "data corruption" state. > > > > > > The one drawback is the need to wait for 10ms before the first transf= er. > > > > > > Tested on Beagleboard XM C. > > > Tested on BBB and AM437x Starter Kit by Felipe Balbi. > > > > > > Signed-off-by: Alexander Kochetkov > > > Tested-by: Felipe Balbi > > > Reviewed-by: Felipe Balbi > >=20 > > This patch recently hit linux-next (as commit 903c3859f77f) and boot > > breakage[1] in next-20141124 on OMAP3530 Beagle and Overo/Tobi boards > > was bisected down to this commit. > >=20 > > Kevin > >=20 > > [1] http://status.armcloud.us/boot/?next-20141124&omap >=20 > btw, based on Kevin's boot test, only OMAP3530 is failing. OK, giving Alexander some time for a fix. If it can't be found, I'll revert this patch. Thanks! --X1bOJ3K7DJ5YkBrT Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJUc4NrAAoJEBQN5MwUoCm2xaEQAK082DTEJDKCWUS19KrPWQVv VoGX6sogqQafjoeKvdr88NSg9IC/YjZMz7yMnnPiMt8/ynW8vuQMjk82mlCnUIvo 0w8Ge+8oD0hIKGZ2BGXWFUvPiqEaJiz3zCVOuLbvuzsmSrr1TsmVL9Y2fUsyrGr0 HfBh7KRM552hA6HC++tFUsMSfFmCiVQLOgOAARi6DSTxcOIZn4GeEwP1PeOqKy8P dScCo/j3cC2MnLtayVuyRL+5PgWW8moqsjP5qOMD/S0jipYB/1VF6WnegWq9oDDJ YaqGAD7gUeCjAlhuFIo9hIO/xiyZs4b78e8qDBAO/Ekeq6vEjsQeyJAGx6dhiUwn bJMLIWHK1Y+lsMlbHP1DcKZ+UQkaufYAJP+nkZ0rxfd24UbPnLF+UgoXg80Y34t5 x2gZBYCq7qxhi1r3PQAVUWig1Et+2f1jndg0LZd7cUTYiOlHQ/oRCyAfUk/BQU1K O8MiH1cHcQsjUPCK3uL96wQyab59wS4uYaR5BHfo977DcDXkAWZebuE9tZN/mucr nDGAgSGajAlI4qcw3sdQCbiKsnxfZvYNSLchISj8OsoWNJZGHA2eNYYm5bW4pr95 7olnxARQg5u+u6JFagMc+sDYcNcwk7BTefZIArvGfU2CanlGtm+aZ3lGkWV1LGpQ R8KQx20SkFFsgViPD5/9 =ckvQ -----END PGP SIGNATURE----- --X1bOJ3K7DJ5YkBrT-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/