From mboxrd@z Thu Jan 1 00:00:00 1970 From: Philby John Subject: Re: [PATCH/RFC 1/1] recover from davinci i2c time out conditions Date: Wed, 22 Jul 2009 16:44:35 +0530 Message-ID: <1248261275.4077.4.camel@localhost.localdomain> References: <1247643267.5981.82.camel@localhost.localdomain> <218571.29671.qm@web50101.mail.re2.yahoo.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <218571.29671.qm-LK+a5U5w+t2B9c0Qi4KiSl5cfvJIxWXgQQ4Iyu8u01E@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Nitin Mahajan Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org, davinci-linux-open-source-VycZQUHpC/PFrsHnngEfi1aTQe2KTcn/@public.gmane.org List-Id: linux-i2c@vger.kernel.org On Wed, 2009-07-22 at 04:03 -0700, Nitin Mahajan wrote: > Hello, > > ----- Original Message ---- > > From: Philby John > > To: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > > Cc: khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org; davinci-linux-open-source-VycZQUHpC/PFrsHnngEfi1aTQe2KTcn/@public.gmane.org > > Sent: Wednesday, July 15, 2009 13:04:27 > > Subject: [PATCH/RFC 1/1] recover from davinci i2c time out conditions > > > > >From dbe7e824d576636bb15b82a20fd2557fddc9a8f7 Mon Sep 17 00:00:00 2001 > > From: Philby John > > Date: Tue, 14 Jul 2009 21:46:47 +0530 > > Subject: [PATCH] Reset i2c bus to come out of time out conditions > > > > Get out of i2c time out condition by resetting > > the i2c bus. The kernel must be robust enough to > > gracefully recover from i2c bus failure without having > > to reset the machine. This is done by first NACKing the slave > > and then resetting the i2c bus after a certain timeout. > > > > Signed-off-by: Philby John > > I tried this on DM6443 based board with 2.6.18 kernel. The result I am posting below. It gives controller time out again and again. > > dhcppc9 login: i2c_davinci i2c_davinci.1: controller timed out > i2c_davinci i2c_davinci.1: initiating i2c bus recovery > i2c_davinci i2c_davinci.1: controller timed out > i2c_davinci i2c_davinci.1: initiating i2c bus recovery There is something gravely wrong about this patch and I would submit a fix shortly incorporating the review comments. But please be aware that I do not guarantee a definitive time line for a fix cause I have much at hand at the moment. Regards, Philby