Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756702AbaDKJW1 (ORCPT ); Fri, 11 Apr 2014 05:22:27 -0400 Received: from mga02.intel.com ([134.134.136.20]:11502 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755998AbaDKJWW (ORCPT ); Fri, 11 Apr 2014 05:22:22 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.97,841,1389772800"; d="scan'208";a="519043386" Date: Fri, 11 Apr 2014 12:29:56 +0300 From: "Westerberg, Mika" To: "Du, Wenkai" Cc: "'linux-i2c@vger.kernel.org'" , "'Wolfram Sang'" , "'linux-kernel@vger.kernel.org'" Subject: Re: [PATCH V2] i2c-designware: Mask all interrupts during i2c controller enable Message-ID: <20140411092956.GE19349@intel.com> References: <7286EAF50D3F4E4AADE7FEECEBF8B5A547FF93E0@ORSMSX110.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7286EAF50D3F4E4AADE7FEECEBF8B5A547FF93E0@ORSMSX110.amr.corp.intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 11, 2014 at 02:03:19AM +0300, Du, Wenkai wrote: > Hi all, > > Updated problem descriptions from Mika's feedback and new test data: > > There have been "i2c_designware 80860F41:00: controller timed out" errors > on a number of Baytrail platforms. The issue is caused by incorrect value in > Interrupt Mask Register (DW_IC_INTR_MASK) when i2c core is being enabled. > This causes call to __i2c_dw_enable() to immediately start the transfer which > leads to timeout. There are 3 failure modes observed: > > 1. Failure in S0 to S3 resume path > > The default value after reset for DW_IC_INTR_MASK is 0x8ff. When we start > the first transaction after resuming from system sleep, TX_EMPTY interrupt > is already unmasked because of the hardware default. > > 2. Failure in normal operational path > > This failure happens rarely and is hard to reproduce. Debug trace showed that > DW_IC_INTR_MASK had value of 0x254 when failure occurred, which meant > TX_EMPTY was unmasked. > > 2. Failure in S3 to S0 suspend path This should probably be 3. > This failure also happens rarely and is hard to reproduce. Adding debug trace > that read DW_IC_INTR_MASK made this failure not reproducible. But from ISR > call trace we could conclude TX_EMPTY was unmasked when problem occurred. > > > The patch masks all interrupts before the controller is enabled to resolve the > faulty DW_IC_INTR_MASK conditions. > > Signed-off-by: Wenkai Du Acked-by: Mika Westerberg -- 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/