From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Subject: Re: [PATCH v2 1/2] i2c: tegra: Better handle case where CPU0 is busy for a long time Date: Mon, 4 May 2020 17:42:26 +0200 Message-ID: <20200504154226.GA614153@ulmo> References: <79f6560e-dbb5-0ae1-49f8-cf1cd95396ec@nvidia.com> <20200427074837.GC3451400@ulmo> <20200427103851.GB24446@kunai> <20200427141922.GD3464906@ulmo> <20200427153106.GA8113@kunai> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="lrZ03NoBR/3+SXJZ" Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Dmitry Osipenko Cc: Wolfram Sang , Jon Hunter , Laxman Dewangan , Manikanta Maddireddy , Vidya Sagar , linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-tegra@vger.kernel.org --lrZ03NoBR/3+SXJZ Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sat, May 02, 2020 at 05:40:35PM +0300, Dmitry Osipenko wrote: > 27.04.2020 18:31, Wolfram Sang =D0=BF=D0=B8=D1=88=D0=B5=D1=82: > >=20 > >> Yes, that bug should be fixed anyway. But that doesn't justify breaking > >> suspend/resume completely, which *is* a regression. > >> > >> Look, I'm not saying that we should drop this patch altogether. All I'm > >> saying is that we should postpone it so that we can: a) get suspend and > >> resume working again (and by doing so make sure no other suspend/resume > >> regressions silently creep in, because that always seems to happen when > >> you're not looking) and b) fix any preexisting issues without possibly > >> scrambling the result with this perhaps unrelated fix. > >> > >> So, again, I think the safest road forward is to back this one out for > >> now, fix whatever this other bug is and once suspend/resume is working > >> properly again we can revisit this patch based on a known-good baselin= e. > >=20 > > I am with you here. I want to add that the proper fix should be > > developed without thinking too much about stable in the first place. > > *When* we have a proper working fix, then we can think about making it > > "more" suitable for backporting. Yet, it may also be a result that older > > kernels need a different solution. Or have no solution at all, in case > > they can't do atomic_transfers and this is needed. > >=20 > > D'accord? > >=20 >=20 > I saw that you submitted the revert of the patches for 5.7, hopefully it > won't result in putting the PCIe driver problem into the back burner. > I'll try not to forget about these patches to resubmit them later on, > once the problem will be resolved :) I can put these two patches into a local development branch to keep track of them. From what I said earlier, it looks like it would be fine to apply these if we also make that runtime PM change (i.e. drop force runtime PM and instead manually invoke runtime PM callbacks, which seems to be in line with what the PM maintainers suggest, as pointed out elsewhere in this thread). How about if I put all of that into a branch and push it to linux-next so that we can get some broader testing? I've already run it through our internal test system, which, while not perfect, is the broadest system I am aware of, and all tests came back positive. I'm not exactly sure I see a real issue with the PCIe driver after those patches are applied. The regulator errors are gone (presumably because the regulators now do get turned off properly) and I don't observe any other issues. Thierry --lrZ03NoBR/3+SXJZ Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEEiOrDCAFJzPfAjcif3SOs138+s6EFAl6wN+AACgkQ3SOs138+ s6FAxQ//Z4QpPdcFLKFZCSCH23KA4t2/646O0Py+XUV421tLkrvkOepTvI2CXWQd vj8cFw6SyA7IKDOEorgHT8nDwJqNTPuEO9eNS33QVlq21ezkibKXAfJH4kbrDr7l pVFJajPsJWvHUS9ULWtWdQKbH7QgAFyiqO5r/b6tOP32uEN+uHAatlUb0ao3ZXnR FZZWkZ4QdX+kxb1RRyLc6+KMIl/XwIdVkgXthRHjhKGT5UQOArj7LrxYQgPaUrqK yFp9ahclAinfGsbPEHbIyxmDTy20SxQbfM9l9Bq/+Tb3NzXfhs5tTnFKx1SImXDY 0fEWZWLiV/uOzwVaAZZ80LRJd2T4VpYGdbX3m06GksmuZRfN74ART7F+dDegECXf Eug96QB2gNLJKaxwP1eBnlLnEobsmAfIKpo4DMcdKD8kcdMQu6TAJSbIl4vT/f19 n0+er/TSPBmVO8c8FlnT2EXmrYvM2uy4BJiE7TdqU7SauexrUxErR5O2mt3Etofb 9aIq3aApVEG1SyU7/Q1HznCJREGv1kB711bgJxE32ZbgpqxdJF7tuTxWX7aV48Os 2HAO4tVeXZWJ5EiciF0v54QrH0TtsLhtbwb6GyIxJvjOLERDffzvKAwKgGXL+1XU Ym4+vPB4bGYtfzASLHrJgMFSTVrHBlrS2v4ZOe5zcBgcBUJk48I= =+3Hv -----END PGP SIGNATURE----- --lrZ03NoBR/3+SXJZ-- 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=-2.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 41598C47257 for ; Mon, 4 May 2020 15:42:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1F4C92073B for ; Mon, 4 May 2020 15:42:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="BkqQFi0+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729431AbgEDPmb (ORCPT ); Mon, 4 May 2020 11:42:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35238 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726509AbgEDPmb (ORCPT ); Mon, 4 May 2020 11:42:31 -0400 Received: from mail-wm1-x344.google.com (mail-wm1-x344.google.com [IPv6:2a00:1450:4864:20::344]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B8DA8C061A0E; Mon, 4 May 2020 08:42:30 -0700 (PDT) Received: by mail-wm1-x344.google.com with SMTP id v4so309405wme.1; Mon, 04 May 2020 08:42:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=HZ0kwajVNDVc6kGRwmzoSlZILWUSqHM0exCohrNVZMM=; b=BkqQFi0+AaEtXI7qFmwdV/U1uRMvXrakoc5iKBneVuNlGZnI9wD220a1BtDxjCqfan o3+VUSP5Xes2bctImgy2dqXoBG9giE3NKvjUiroyuy8bb4llt9xoBuoXGcnVjy7KRCLO XAinVgEqxy5poa1UXsg47JMsXE3BCfrsL/vU2JByPuXh0Yorm1My3FKYKH/esydeNXeJ XU6zqtt8uzGpQJJfYRaVmFQ6s2MbORUkXEAswxHpkMbuWgcjzgkEd9XPcwPqcaSL1XMM Xjtr62lGe/M+G1yQjH/CJNg/sZANHFkQyUtA6JH7LyK2EWVhSlBAlw6FCHn4T6BaJYWm vwrg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=HZ0kwajVNDVc6kGRwmzoSlZILWUSqHM0exCohrNVZMM=; b=OWtlDEoS0BVNtMjOxB2l4isKiEfT9QvmayhGgdvvOLRqPNVhA2cKwubtXVjEP3XCgH 0VH5bmJfk0beIBk+GoLkabNMwgPqEv/Thgduu1rmJbmFXe+yIl80jo5YZPUd0TRQ/vsQ Mv6EiSv1o2NFLVqm0iErWajRbWc6lm7S4bpuel8oBGRyDZLudEdJtFNlqrHgawTgq+RV t/19wf0K/4GB5NHnkz+/yERd0W6EcOs5PIWinTBsv7pwJTkjuIN5SdxlXAgJII5ShNTU z5RqjxjewfhGjvhbsp8s7ItvCHe8vvAbEODBfWduEwr8GpokHGOv0V2wFlJl3aSVt4zp tt5w== X-Gm-Message-State: AGi0PubKRUuI8snmldx0CBRz134GOYYe7Kuwa05LZ8xmB/SJVLnGUy0q 8TBaYfiSPRDxSNU9+2ci7j8= X-Google-Smtp-Source: APiQypLpDC/GMx6y2l/BDiHCciUPwVbk3Hj60EHeltjqMQ2qh8snhlQDpB1WaaKTBiTwxh7Uv4DY+g== X-Received: by 2002:a1c:c345:: with SMTP id t66mr16418509wmf.189.1588606949426; Mon, 04 May 2020 08:42:29 -0700 (PDT) Received: from localhost (p2E5BE57B.dip0.t-ipconnect.de. [46.91.229.123]) by smtp.gmail.com with ESMTPSA id q184sm14544893wma.25.2020.05.04.08.42.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 04 May 2020 08:42:27 -0700 (PDT) Date: Mon, 4 May 2020 17:42:26 +0200 From: Thierry Reding To: Dmitry Osipenko Cc: Wolfram Sang , Jon Hunter , Laxman Dewangan , Manikanta Maddireddy , Vidya Sagar , linux-i2c@vger.kernel.org, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/2] i2c: tegra: Better handle case where CPU0 is busy for a long time Message-ID: <20200504154226.GA614153@ulmo> References: <79f6560e-dbb5-0ae1-49f8-cf1cd95396ec@nvidia.com> <20200427074837.GC3451400@ulmo> <20200427103851.GB24446@kunai> <20200427141922.GD3464906@ulmo> <20200427153106.GA8113@kunai> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="lrZ03NoBR/3+SXJZ" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.13.1 (2019-12-14) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --lrZ03NoBR/3+SXJZ Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sat, May 02, 2020 at 05:40:35PM +0300, Dmitry Osipenko wrote: > 27.04.2020 18:31, Wolfram Sang =D0=BF=D0=B8=D1=88=D0=B5=D1=82: > >=20 > >> Yes, that bug should be fixed anyway. But that doesn't justify breaking > >> suspend/resume completely, which *is* a regression. > >> > >> Look, I'm not saying that we should drop this patch altogether. All I'm > >> saying is that we should postpone it so that we can: a) get suspend and > >> resume working again (and by doing so make sure no other suspend/resume > >> regressions silently creep in, because that always seems to happen when > >> you're not looking) and b) fix any preexisting issues without possibly > >> scrambling the result with this perhaps unrelated fix. > >> > >> So, again, I think the safest road forward is to back this one out for > >> now, fix whatever this other bug is and once suspend/resume is working > >> properly again we can revisit this patch based on a known-good baselin= e. > >=20 > > I am with you here. I want to add that the proper fix should be > > developed without thinking too much about stable in the first place. > > *When* we have a proper working fix, then we can think about making it > > "more" suitable for backporting. Yet, it may also be a result that older > > kernels need a different solution. Or have no solution at all, in case > > they can't do atomic_transfers and this is needed. > >=20 > > D'accord? > >=20 >=20 > I saw that you submitted the revert of the patches for 5.7, hopefully it > won't result in putting the PCIe driver problem into the back burner. > I'll try not to forget about these patches to resubmit them later on, > once the problem will be resolved :) I can put these two patches into a local development branch to keep track of them. From what I said earlier, it looks like it would be fine to apply these if we also make that runtime PM change (i.e. drop force runtime PM and instead manually invoke runtime PM callbacks, which seems to be in line with what the PM maintainers suggest, as pointed out elsewhere in this thread). How about if I put all of that into a branch and push it to linux-next so that we can get some broader testing? I've already run it through our internal test system, which, while not perfect, is the broadest system I am aware of, and all tests came back positive. I'm not exactly sure I see a real issue with the PCIe driver after those patches are applied. The regulator errors are gone (presumably because the regulators now do get turned off properly) and I don't observe any other issues. 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