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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 8A9E1C433E0 for ; Wed, 3 Jun 2020 13:51:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 627DF20772 for ; Wed, 3 Jun 2020 13:51:26 +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="nlOdirDb" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726119AbgFCNvZ (ORCPT ); Wed, 3 Jun 2020 09:51:25 -0400 Received: from mail27.static.mailgun.info ([104.130.122.27]:63487 "EHLO mail27.static.mailgun.info" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725943AbgFCNvX (ORCPT ); Wed, 3 Jun 2020 09:51:23 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1591192283; h=Message-ID: References: In-Reply-To: Subject: Cc: To: From: Date: Content-Transfer-Encoding: Content-Type: MIME-Version: Sender; bh=4th+09S0iCW1XVvsnSYykoMMaed1cUFlHMRPNaY08ZY=; b=nlOdirDbqXIipVuMKblvTIyJRBOkaLZs/tbbc/Ezk5A9nwPjnlkGUJa8YIGAPA94Vs8rtMUo CzabR2pE6aZ1id413mP9qFD5OYAK0WYdpPnavDgNGXD12bHGMGY9Vf/Oq1/tdjrpcD5cyO8w QmrGQw/6/ePaTJGryrPwRtf89mA= X-Mailgun-Sending-Ip: 104.130.122.27 X-Mailgun-Sid: WyI1MzIzYiIsICJsaW51eC1hcm0tbXNtQHZnZXIua2VybmVsLm9yZyIsICJiZTllNGEiXQ== Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n03.prod.us-west-2.postgun.com with SMTP id 5ed7aac98e09c0ae098b58eb (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Wed, 03 Jun 2020 13:51:05 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 7D522C43395; Wed, 3 Jun 2020 13:51:05 +0000 (UTC) Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: saiprakash.ranjan) by smtp.codeaurora.org (Postfix) with ESMTPSA id CD2FEC433C6; Wed, 3 Jun 2020 13:51:04 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Wed, 03 Jun 2020 19:21:04 +0530 From: Sai Prakash Ranjan To: Robin Murphy Cc: Mathieu Poirier , Suzuki K Poulose , Mike Leach , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, coresight@lists.linaro.org, Stephen Boyd Subject: Re: [PATCH 2/2] coresight: tmc: Add shutdown callback for TMC ETR/ETF In-Reply-To: <68444180-3ebe-8988-493a-fdd1dff994b6@arm.com> References: <28123d1e19f235f97555ee36a5ed8b52d20cbdea.1590947174.git.saiprakash.ranjan@codeaurora.org> <20200601212858.GB24287@xps15> <1549935cf69ac3a006f32eb278821027@codeaurora.org> <6c1a4fbd-98cb-a49c-0ced-1318d5d5e7c8@arm.com> <7fe5762b5cb8f87e988232922d06c55d@codeaurora.org> <68444180-3ebe-8988-493a-fdd1dff994b6@arm.com> Message-ID: X-Sender: saiprakash.ranjan@codeaurora.org User-Agent: Roundcube Webmail/1.3.9 Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Hi Robin, On 2020-06-03 19:10, Robin Murphy wrote: > On 2020-06-03 13:26, Sai Prakash Ranjan wrote: >> Hi Robin, >> >> On 2020-06-03 17:51, Robin Murphy wrote: >>> On 2020-06-03 13:00, Sai Prakash Ranjan wrote: >>>> Hi Robin, Mathieu >>>> >>>> On 2020-06-03 17:07, Robin Murphy wrote: >>>>> On 2020-06-01 22:28, Mathieu Poirier wrote: >>>>>> That being said I'm sure that dependencies on an IOMMU isn't a >>>>>> problem confined >>>>>> to coresight. I am adding Robin Murphy, who added this commit [1], >>>>>> to the thread >>>>>> in the hope that he can provide guidance on the right way to do >>>>>> this. >>>>> >>>>> Right, it's not specific to CoreSight, and it's not even specific >>>>> to >>>>> IOMMUs really. In short, blame kexec ;) >>>>> >>>> >>>> Yes it is not specific to coresight, we are targeting this for all >>>> consumers/clients of SMMU(atleast on SC7180 SoC). We have display >>>> throwing >>>> NoC/interconnect errors[1] during reboot after SMMU is disabled. >>>> This is also not specific to kexec either as you explained here [2] >>>> about >>>> a case with display which is exacly what is happening in our system >>>> [1]. >>> >>> Sure, but those instances are begging the question of why the SMMU is >>> disabled at reboot in the first place ;) >>> >> >> That is what happens in SMMU shutdown callback right? It is the >> reboot/shutdown flow. > > Yes, that's where it happens, but my point is *why* it happens at all. > > hint: `git log --grep=shutdown drivers/iommu/` > Ah my change :) > If we could assume the system is always about to be powered off or > reset, we wouldn't need to do anything to the SMMU either ;) > Are you hinting at removing SMMU shutdown callback altogether ;) Thanks, Sai -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation