From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Osipenko Subject: [PATCH v1 0/2] NVIDIA Tegra I2C synchronization correction Date: Thu, 19 Mar 2020 23:11:38 +0300 Message-ID: <20200319201140.17451-1-digetx@gmail.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: Received: from mail-lf1-f68.google.com ([209.85.167.68]:34416 "EHLO mail-lf1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725747AbgCSUMh (ORCPT ); Thu, 19 Mar 2020 16:12:37 -0400 Sender: linux-i2c-owner@vger.kernel.org List-Id: linux-i2c@vger.kernel.org To: Thierry Reding , Jonathan Hunter , Laxman Dewangan , Wolfram Sang Cc: linux-i2c@vger.kernel.org, linux-tegra@vger.kernel.org, Vinod Koul , Dan Williams , dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org Hello, Recently I found a way to reliably reproduce I2C timeouts that happen due to improper synchronizations made by the I2C driver. It's quite easy to reproduce the problem when memory is running on a lower freq + there is some memory activity + CPU could get busy for a significant time. This is the case when KASAN is enabled and CPU is busy while accessing FS via NFS. This small series addresses the found problems. Please note that the "Synchronize DMA before termination" patch implicitly depends on the "dmaengine: tegra-apb: Improve DMA synchronization" patch, which is sent separately, otherwise DMA synchronization won't happen. Dmitry Osipenko (2): i2c: tegra: Better handle case where CPU0 is busy for a long time i2c: tegra: Synchronize DMA before termination drivers/i2c/busses/i2c-tegra.c | 27 ++++++++++++++++++++------- 1 file changed, 20 insertions(+), 7 deletions(-) -- 2.25.1