From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 08A09C433EA for ; Mon, 27 Jul 2020 08:36:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D5B662074F for ; Mon, 27 Jul 2020 08:36:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="OWqkBeyh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726475AbgG0Igq (ORCPT ); Mon, 27 Jul 2020 04:36:46 -0400 Received: from m43-7.mailgun.net ([69.72.43.7]:60795 "EHLO m43-7.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727071AbgG0Igp (ORCPT ); Mon, 27 Jul 2020 04:36:45 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1595839005; h=Content-Transfer-Encoding: Content-Type: In-Reply-To: MIME-Version: Date: Message-ID: From: References: Cc: To: Subject: Sender; bh=JqWfd/1AwzywENu929p5CV6pTKTw5ZyiTiaOJDpxEvU=; b=OWqkBeyh5Wk/nfrKGN2hybyHkqGP5cZYqOEwtqoD+nciRTBFxSCqjB/zb4sP9cpv7g8Sk0HL fVYRiy7TLzGmIZ08+nurkQrWWA+kiONB1A31k8C7EI5I8eOyyMMHGIuTg8bZMiXQsk9YpyXF EhBxMs/ieMEtALgcg2H5L7Cvr8w= X-Mailgun-Sending-Ip: 69.72.43.7 X-Mailgun-Sid: WyI5ZGU3NiIsICJsaW51eC1pMmNAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n09.prod.us-west-2.postgun.com with SMTP id 5f1e921cc7e7bf09e0ce2347 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Mon, 27 Jul 2020 08:36:44 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 3B4E6C4339C; Mon, 27 Jul 2020 08:36:44 +0000 (UTC) Received: from [192.168.0.13] (unknown [183.83.138.47]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: akashast) by smtp.codeaurora.org (Postfix) with ESMTPSA id 5B086C433C9; Mon, 27 Jul 2020 08:36:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 5B086C433C9 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=none smtp.mailfrom=akashast@codeaurora.org Subject: Re: [PATCH v2] i2c: i2c-qcom-geni: Fix DMA transfer race To: Wolfram Sang , Douglas Anderson Cc: swboyd@chromium.org, msavaliy@codeaurora.org, Sai Prakash Ranjan , Rajendra Nayak , Alok Chauhan , Andy Gross , Bjorn Andersson , Girish Mahadevan , Karthikeyan Ramasubramanian , Sagar Dharia , linux-arm-msm@vger.kernel.org, linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org References: <20200722145948.v2.1.I7efdf6efaa6edadbb690196cd4fbe3392a582c89@changeid> <20200723195634.GA908@ninjato> <20200726124747.GA16169@ninjato> From: Akash Asthana Message-ID: Date: Mon, 27 Jul 2020 14:06:36 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200726124747.GA16169@ninjato> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-i2c-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org On 7/26/2020 6:17 PM, Wolfram Sang wrote: > On Thu, Jul 23, 2020 at 09:56:34PM +0200, Wolfram Sang wrote: >> On Wed, Jul 22, 2020 at 03:00:21PM -0700, Douglas Anderson wrote: >>> When I have KASAN enabled on my kernel and I start stressing the >>> touchscreen my system tends to hang. The touchscreen is one of the >>> only things that does a lot of big i2c transfers and ends up hitting >>> the DMA paths in the geni i2c driver. It appears that KASAN adds >>> enough delay in my system to tickle a race condition in the DMA setup >>> code. >>> >>> When the system hangs, I found that it was running the geni_i2c_irq() >>> over and over again. It had these: >>> >>> m_stat = 0x04000080 >>> rx_st = 0x30000011 >>> dm_tx_st = 0x00000000 >>> dm_rx_st = 0x00000000 >>> dma = 0x00000001 >>> >>> Notably we're in DMA mode but are getting M_RX_IRQ_EN and >>> M_RX_FIFO_WATERMARK_EN over and over again. >>> >>> Putting some traces in geni_i2c_rx_one_msg() showed that when we >>> failed we were getting to the start of geni_i2c_rx_one_msg() but were >>> never executing geni_se_rx_dma_prep(). >>> >>> I believe that the problem here is that we are starting the geni >>> command before we run geni_se_rx_dma_prep(). If a transfer makes it >>> far enough before we do that then we get into the state I have >>> observed. Let's change the order, which seems to work fine. >>> >>> Although problems were seen on the RX path, code inspection suggests >>> that the TX should be changed too. Change it as well. >>> >>> Fixes: 37692de5d523 ("i2c: i2c-qcom-geni: Add bus driver for the Qualcomm GENI I2C controller") >>> Signed-off-by: Douglas Anderson >>> Tested-by: Sai Prakash Ranjan >>> Reviewed-by: Akash Asthana >> Applied to for-current, thanks! > Glad we got this sorted. I just wondered that Alok wasn't part of the > discussion. Is he still interested in maintaining the driver? Also > because there is an unprocessed patch left for this driver: > > http://patchwork.ozlabs.org/project/linux-i2c/patch/20191103212204.13606-1-colin.king@canonical.com/ Alok has moved out of GENI team, he no longer supports GENI I2C drivers. I have posted a patch to update maintainers list. Patch: https://patchwork.kernel.org/patch/11686541/ [MAINTAINERS: Update Geni I2C maintainers list] Also, Girish Mahadevan, Sagar Dharia and Karthikeyan Ramasubramanian  no longer supports GENI drivers. Regards, Akash > -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,\na Linux Foundation Collaborative Project