Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754879AbaKXTKU (ORCPT ); Mon, 24 Nov 2014 14:10:20 -0500 Received: from bear.ext.ti.com ([192.94.94.41]:47434 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754427AbaKXTKQ (ORCPT ); Mon, 24 Nov 2014 14:10:16 -0500 Date: Mon, 24 Nov 2014 13:10:23 -0600 From: Felipe Balbi To: Kevin Hilman CC: Alexander Kochetkov , Felipe Balbi , Tony Lindgren , linux-omap , , lkml , Wolfram Sang Subject: Re: [PATCH v3 2/4] i2c: omap: implement workaround for handling invalid BB-bit values Message-ID: <20141124191023.GG25712@saruman> Reply-To: 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> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="bO4vSxwwZtUjUWHo" Content-Disposition: inline In-Reply-To: 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 --bO4vSxwwZtUjUWHo Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable 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 doe= sn't > > correspond to the current bus state. It may happen what BB-bit will be = 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 completed = 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 transfer. > > > > 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 btw, based on Kevin's boot test, only OMAP3530 is failing. --=20 balbi --bO4vSxwwZtUjUWHo Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJUc4KeAAoJEIaOsuA1yqRECs0P/j0/YbGcdhL8RQSJlX3WaQWW BiTrZhDA0dS27z14x7dnyO0xdl1B2gxUAfDl3gATWq2ILP206Thn4tbO5l3VJ0Hv LfO2MLKmd+zWuaFAo4pCFg4makM5MEDw0ctFDeg4b44hH5hVebGcV/pUf9wS5K/v 75Fd02xKKtNacuAr7J+JprQvbvUZ0K54gWco/VeDN0sbE4Gcq3a2opV1mooPOcWK k/qZZ9aDtSsUT9sT97h5c8tDCVp0/PxUZirzkRCq9M5dV2mkj0hQZM9wBSbemCJ5 33YqEiz6oKSOpxcsMd2XuLbjsum/r5ciraCzjlPKkSqVIxAP4NNXzU7U5iScuxI5 fVtfomz1SkTgAkeRsGF7AW6fmhpDt9aEcvjJPLSYx200nSn6QcE095M8BMY2yizF GdZlA088FjMWWyMbgeko8PvjJJI4WTzQyKGpxkoqufIIxWicdKz4kQn/k1JK0Nsb 9NcbAZZpWQ1jfkl45pPAJFqrfRhNZNnHaXahNB+9tPML7V8JMKoSC9DBbc9wPGRv shS9LJ6gnbKXA09T58pALPKohmxB1SiI4ijE8NhogiXzfM/rjoiwqvNxgXuvOV1l QnSDG1oppYCziUjKI19BfPHUddLQjGCZLNNNwuo1j2gv0HuXlAm4c8Pi7OGsD8Jm MUM3miJZZZXeAPqAwsAN =UY+Q -----END PGP SIGNATURE----- --bO4vSxwwZtUjUWHo-- -- 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/