From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Herrenschmidt Subject: Re: [PATCH v7 4/5] i2c: aspeed: added driver for Aspeed I2C Date: Tue, 09 May 2017 09:15:07 +0200 Message-ID: <1494314107.25766.442.camel@kernel.crashing.org> References: <20170424181818.2754-1-brendanhiggins@google.com> <20170424181818.2754-5-brendanhiggins@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Brendan Higgins , Wolfram Sang , Rob Herring , Mark Rutland , Thomas Gleixner , Jason Cooper , Marc Zyngier , Joel Stanley , Vladimir Zapolskiy , Kachalov Anton , =?ISO-8859-1?Q?C=E9dric?= Le Goater Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Linux Kernel Mailing List , OpenBMC Maillist , Ryan Chen List-Id: linux-i2c@vger.kernel.org On Mon, 2017-05-08 at 16:28 -0700, Brendan Higgins wrote: > > I am curious what everyone thinks about this. It seemed that, earlier > on, people did not like me disabling multi-master mode, but I think > that it would make bus recovery not work as well. Given that, I think > it makes the most sense to provide a device tree option either to > enable multi-master support or disable it. Thoughts? I think we probably want to keep it enabled yes. Another reason is that SMBus notifications are in effect a type of multi-master (well slave really), and we should really add support for them even when the slave is not enabled. We are hitting some PMbus devices that apparently can't be prevented from sending those and that's causing issues. Cheers, Ben. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3wMVyj157BzDqJ8 for ; Tue, 9 May 2017 17:15:56 +1000 (AEST) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.13.8) with ESMTP id v497Ew7l006609; Tue, 9 May 2017 02:14:59 -0500 Message-ID: <1494314107.25766.442.camel@kernel.crashing.org> Subject: Re: [PATCH v7 4/5] i2c: aspeed: added driver for Aspeed I2C From: Benjamin Herrenschmidt To: Brendan Higgins , Wolfram Sang , Rob Herring , Mark Rutland , Thomas Gleixner , Jason Cooper , Marc Zyngier , Joel Stanley , Vladimir Zapolskiy , Kachalov Anton , =?ISO-8859-1?Q?C=E9dric?= Le Goater Cc: linux-i2c@vger.kernel.org, devicetree@vger.kernel.org, Linux Kernel Mailing List , OpenBMC Maillist , Ryan Chen Date: Tue, 09 May 2017 09:15:07 +0200 In-Reply-To: References: <20170424181818.2754-1-brendanhiggins@google.com> <20170424181818.2754-5-brendanhiggins@google.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.22.6 (3.22.6-1.fc25) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-BeenThere: openbmc@lists.ozlabs.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Development list for OpenBMC List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 09 May 2017 07:15:57 -0000 On Mon, 2017-05-08 at 16:28 -0700, Brendan Higgins wrote: > > I am curious what everyone thinks about this. It seemed that, earlier > on, people did not like me disabling multi-master mode, but I think > that it would make bus recovery not work as well. Given that, I think > it makes the most sense to provide a device tree option either to > enable multi-master support or disable it. Thoughts? I think we probably want to keep it enabled yes. Another reason is that SMBus notifications are in effect a type of multi-master (well slave really), and we should really add support for them even when the slave is not enabled. We are hitting some PMbus devices that apparently can't be prevented from sending those and that's causing issues. Cheers, Ben.