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=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,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 046F7C43331 for ; Thu, 26 Mar 2020 10:18:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C11FB2077D for ; Thu, 26 Mar 2020 10:18:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="FCN/IW1i" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727909AbgCZKSC (ORCPT ); Thu, 26 Mar 2020 06:18:02 -0400 Received: from mail-wr1-f68.google.com ([209.85.221.68]:35007 "EHLO mail-wr1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727697AbgCZKSC (ORCPT ); Thu, 26 Mar 2020 06:18:02 -0400 Received: by mail-wr1-f68.google.com with SMTP id d5so7054622wrn.2 for ; Thu, 26 Mar 2020 03:18:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=subject:to:cc:references:from:autocrypt:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=TuGcEmjsgWx5vkbaGQbJP6pq01weNVcMPFQ46kPq2GA=; b=FCN/IW1i6Ae1Abgx+BHCWGgjDV4PljudACUyurYffVcrl751JV4hL3GjXxy5JRn0mJ oOCPrjIXlDAh+I3L+m6p2Ou/ZcXVZqGOSsWvVJc57pYDKKMEFodt+Y544Ho5I/+mi5ca 3neQSyBFt1NRKqONQk90pni9jR/daUTavcl4mkeZUZ+wQkNo+plY6giOx4BvhaOztzvQ jyAkGaZzL7YXjloawH73cTd5vEbjD9ZMJnRXNZvyYaxD7Kzf/Kyjc7xPZ6e05aFkYMjT f8pP+FESYeq4OVe9u441QzvTz0URcPFlPcnAeG3CP/U2OrBEWN8AQUWDGB9SyhUizShP MB1A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:autocrypt :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=TuGcEmjsgWx5vkbaGQbJP6pq01weNVcMPFQ46kPq2GA=; b=K4vvbLnTAiu1i4T48KSTlkoZgTjh5RZikJsq2Pwbh6DegOSsZeaXm+5nQklyTiMOJX OPnL6dunIkSNvemxkf6zIxtASBa6qaEn+/BPZntLSREdGWHA8L+/v3isVU6FzenTSOfi wN32Uy/ng9T2zAGlGIt87wpWQ/7zC7sGSBRnEQF1e3fhIcj7bha6L9DWtoLfR2AQzIgP UE/IKS9JS/7uXmSeUjsOogoBl8hVMrkzzL+yzWEyIWZdMWjuzJsmP3H49IgU5JbvQdDS bf2pShz1mUK56rEwGxpjab/KiUAdsSoTRTnDi9TXCyJTEYv9a01USUA4pLVg9Gv+o+Cq vqQA== X-Gm-Message-State: ANhLgQ0/aRkPzYOidXhK1dkFtsV6e7mvv+7LrdeD1m//r1XWCzg+s5VN +poZ6OjqN081ds/xzwe+9bL7CQ== X-Google-Smtp-Source: ADFU+vuuMx4VVfl4Fnqixu7nbT1uz5O+5bS9z0rydNlzSTGhB9T/JwRCNhVPQPxgdIPGVBYspYnhlA== X-Received: by 2002:adf:afdb:: with SMTP id y27mr8609002wrd.208.1585217879465; Thu, 26 Mar 2020 03:17:59 -0700 (PDT) Received: from ?IPv6:2a01:e34:ed2f:f020:d702:b4a5:b331:1282? ([2a01:e34:ed2f:f020:d702:b4a5:b331:1282]) by smtp.googlemail.com with ESMTPSA id v11sm3009604wrm.43.2020.03.26.03.17.58 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 26 Mar 2020 03:17:58 -0700 (PDT) Subject: Re: [tip: timers/core] clocksource/drivers/timer-probe: Avoid creating dead devices To: Saravana Kannan , Thomas Gleixner Cc: Ionela Voinescu , LKML , linux-tip-commits@vger.kernel.org, x86 , liviu.dudau@arm.com, sudeep.holla@arm.com, Lorenzo Pieralisi , Jon Hunter References: <20200111052125.238212-1-saravanak@google.com> <158460766637.28353.11325960928759668587.tip-bot2@tip-bot2> <20200324175955.GA16972@arm.com> <87lfnoxg2a.fsf@nanos.tec.linutronix.de> From: Daniel Lezcano Autocrypt: addr=daniel.lezcano@linaro.org; prefer-encrypt=mutual; keydata= xsFNBFv/yykBEADDdW8RZu7iZILSf3zxq5y8YdaeyZjI/MaqgnvG/c3WjFaunoTMspeusiFE sXvtg3ehTOoyD0oFjKkHaia1Zpa1m/gnNdT/WvTveLfGA1gH+yGes2Sr53Ht8hWYZFYMZc8V 2pbSKh8wepq4g8r5YI1XUy9YbcTdj5mVrTklyGWA49NOeJz2QbfytMT3DJmk40LqwK6CCSU0 9Ed8n0a+vevmQoRZJEd3Y1qXn2XHys0F6OHCC+VLENqNNZXdZE9E+b3FFW0lk49oLTzLRNIq 0wHeR1H54RffhLQAor2+4kSSu8mW5qB0n5Eb/zXJZZ/bRiXmT8kNg85UdYhvf03ZAsp3qxcr xMfMsC7m3+ADOtW90rNNLZnRvjhsYNrGIKH8Ub0UKXFXibHbafSuq7RqyRQzt01Ud8CAtq+w P9EftUysLtovGpLSpGDO5zQ++4ZGVygdYFr318aGDqCljKAKZ9hYgRimPBToDedho1S1uE6F 6YiBFnI3ry9+/KUnEP6L8Sfezwy7fp2JUNkUr41QF76nz43tl7oersrLxHzj2dYfWUAZWXva wW4IKF5sOPFMMgxoOJovSWqwh1b7hqI+nDlD3mmVMd20VyE9W7AgTIsvDxWUnMPvww5iExlY eIC0Wj9K4UqSYBOHcUPrVOKTcsBVPQA6SAMJlt82/v5l4J0pSQARAQABzSpEYW5pZWwgTGV6 Y2FubyA8ZGFuaWVsLmxlemNhbm9AbGluYXJvLm9yZz7Cwa4EEwEIAEECGwEFCwkIBwIGFQoJ CAsCBBYCAwECHgECF4ACGQEWIQQk1ibyU76eh+bOW/SP9LjScWdVJwUCXAkeagUJDRnjhwAh CRCP9LjScWdVJxYhBCTWJvJTvp6H5s5b9I/0uNJxZ1Un69gQAJK0ODuKzYl0TvHPU8W7uOeu U7OghN/DTkG6uAkyqW+iIVi320R5QyXN1Tb6vRx6+yZ6mpJRW5S9fO03wcD8Sna9xyZacJfO UTnpfUArs9FF1pB3VIr95WwlVoptBOuKLTCNuzoBTW6jQt0sg0uPDAi2dDzf+21t/UuF7I3z KSeVyHuOfofonYD85FkQJN8lsbh5xWvsASbgD8bmfI87gEbt0wq2ND5yuX+lJK7FX4lMO6gR ZQ75g4KWDprOO/w6ebRxDjrH0lG1qHBiZd0hcPo2wkeYwb1sqZUjQjujlDhcvnZfpDGR4yLz 5WG+pdciQhl6LNl7lctNhS8Uct17HNdfN7QvAumYw5sUuJ+POIlCws/aVbA5+DpmIfzPx5Ak UHxthNIyqZ9O6UHrVg7SaF3rvqrXtjtnu7eZ3cIsfuuHrXBTWDsVwub2nm1ddZZoC530BraS d7Y7eyKs7T4mGwpsi3Pd33Je5aC/rDeF44gXRv3UnKtjq2PPjaG/KPG0fLBGvhx0ARBrZLsd 5CTDjwFA4bo+pD13cVhTfim3dYUnX1UDmqoCISOpzg3S4+QLv1bfbIsZ3KDQQR7y/RSGzcLE z164aDfuSvl+6Myb5qQy1HUQ0hOj5Qh+CzF3CMEPmU1v9Qah1ThC8+KkH/HHjPPulLn7aMaK Z8t6h7uaAYnGzjMEXZLIEhYJKwYBBAHaRw8BAQdAGdRDglTydmxI03SYiVg95SoLOKT5zZW1 7Kpt/5zcvt3CwhsEGAEIACAWIQQk1ibyU76eh+bOW/SP9LjScWdVJwUCXZLIEgIbAgCvCRCP 9LjScWdVJ40gBBkWCAAdFiEEbinX+DPdhovb6oob3uarTi9/eqYFAl2SyBIAIQkQ3uarTi9/ eqYWIQRuKdf4M92Gi9vqihve5qtOL396pnZGAP0c3VRaj3RBEOUGKxHzcu17ZUnIoJLjpHdk NfBnWU9+UgD/bwTxE56Wd8kQZ2e2UTy4BM8907FsJgAQLL4tD2YZggwWIQQk1ibyU76eh+bO W/SP9LjScWdVJ5CaD/0YQyfUzjpR1GnCSkbaLYTEUsyaHuWPI/uSpKTtcbttpYv+QmYsIwD9 8CeH3zwY0Xl/1fE9Hy59z6Vxv9YVapLx0nPDOA1zDVNq2MnutxHb8t+Imjz4ERCxysqtfYrv gao3E/h0c8SEeh+bh5MkjwmU8CwZ3doWyiVdULKESe7/Gs5OuhFzaDVPCpWdsKdCAGyUuP/+ qRWwKGVpWP0Rrt6MTK24Ibeu3xEZO8c3XOEXH5d9nf6YRqBEIizAecoCr00E9c+6BlRS0AqR OQC3/Mm7rWtco3+WOridqVXkko9AcZ8AiM5nu0F8AqYGKg0y7vkL2LOP8us85L0p57MqIR1u gDnITlTY0x4RYRWJ9+k7led5WsnWlyv84KNzbDqQExTm8itzeZYW9RvbTS63r/+FlcTa9Cz1 5fW3Qm0BsyECvpAD3IPLvX9jDIR0IkF/BQI4T98LQAkYX1M/UWkMpMYsL8tLObiNOWUl4ahb PYi5Yd8zVNYuidXHcwPAUXqGt3Cs+FIhihH30/Oe4jL0/2ZoEnWGOexIFVFpue0jdqJNiIvA F5Wpx+UiT5G8CWYYge5DtHI3m5qAP9UgPuck3N8xCihbsXKX4l8bdHfziaJuowief7igeQs/ WyY9FnZb0tl29dSa7PdDKFWu+B+ZnuIzsO5vWMoN6hMThTl1DxS+jc7ATQRb/8z6AQgAvSkg 5w7dVCSbpP6nXc+i8OBz59aq8kuL3YpxT9RXE/y45IFUVuSc2kuUj683rEEgyD7XCf4QKzOw +XgnJcKFQiACpYAowhF/XNkMPQFspPNM1ChnIL5KWJdTp0DhW+WBeCnyCQ2pzeCzQlS/qfs3 dMLzzm9qCDrrDh/aEegMMZFO+reIgPZnInAcbHj3xUhz8p2dkExRMTnLry8XXkiMu9WpchHy XXWYxXbMnHkSRuT00lUfZAkYpMP7La2UudC/Uw9WqGuAQzTqhvE1kSQe0e11Uc+PqceLRHA2 bq/wz0cGriUrcCrnkzRmzYLoGXQHqRuZazMZn2/pSIMZdDxLbwARAQABwsGNBBgBCAAgFiEE JNYm8lO+nofmzlv0j/S40nFnVScFAlv/zPoCGwwAIQkQj/S40nFnVScWIQQk1ibyU76eh+bO W/SP9LjScWdVJ/g6EACFYk+OBS7pV9KZXncBQYjKqk7Kc+9JoygYnOE2wN41QN9Xl0Rk3wri qO7PYJM28YjK3gMT8glu1qy+Ll1bjBYWXzlsXrF4szSqkJpm1cCxTmDOne5Pu6376dM9hb4K l9giUinI4jNUCbDutlt+Cwh3YuPuDXBAKO8YfDX2arzn/CISJlk0d4lDca4Cv+4yiJpEGd/r BVx2lRMUxeWQTz+1gc9ZtbRgpwoXAne4iw3FlR7pyg3NicvR30YrZ+QOiop8psWM2Fb1PKB9 4vZCGT3j2MwZC50VLfOXC833DBVoLSIoL8PfTcOJOcHRYU9PwKW0wBlJtDVYRZ/CrGFjbp2L eT2mP5fcF86YMv0YGWdFNKDCOqOrOkZVmxai65N9d31k8/O9h1QGuVMqCiOTULy/h+FKpv5q t35tlzA2nxPOX8Qj3KDDqVgQBMYJRghZyj5+N6EKAbUVa9Zq8xT6Ms2zz/y7CPW74G1GlYWP i6D9VoMMi6ICko/CXUZ77OgLtMsy3JtzTRbn/wRySOY2AsMgg0Sw6yJ0wfrVk6XAMoLGjaVt X4iPTvwocEhjvrO4eXCicRBocsIB2qZaIj3mlhk2u4AkSpkKm9cN0KWYFUxlENF4/NKWMK+g fGfsCsS3cXXiZpufZFGr+GoHwiELqfLEAQ9AhlrHGCKcgVgTOI6NHg== Message-ID: <4be7d1bf-9039-4ca0-02ac-d90d01cf1c4b@linaro.org> Date: Thu, 26 Mar 2020 11:17:57 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Saravana, On 25/03/2020 23:56, Saravana Kannan wrote: > On Wed, Mar 25, 2020 at 2:47 PM Thomas Gleixner > wrote: >> >> Saravana Kannan writes: >>> On Tue, Mar 24, 2020 at 11:34 AM Saravana Kannan >>> wrote: I took a closer look. So two >>> different drivers [1] [2] are saying they know how to handle >>> "arm,vexpress-sysreg" and are expecting to run at the same >>> time. That seems a bit unusual to me. I wonder if this is a >>> violation of the device-driver model because this expectation >>> would never be allowed if these device drivers were actual >>> drivers registered with driver-core. But that's a discussion >>> for another time. >>> >>> To fix this issue you are facing, this patch should work: >>> https://lore.kernel.org/lkml/20200324195302.203115-1-saravanak@google.com/T/#u >> >> >>> >>> >>> > Sorry, that's not a fix. That's a crude hack. > > If device nodes are being handled by drivers without binding a > driver to struct devices, then not setting OF_POPULATED is wrong. > So the original patch sets it. There are also very valid reasons > for allowing OF_POPULATED to be cleared by a driver as discussed > here [1]. > > The approach of the original patch (setting the flag and letting > the driver sometimes clear it) is also followed by many other > frameworks like irq, clk, i2c, etc. Even ingenic-timer.c already > does it for the exact same reason. > > So, why is the vexpress fix a crude hack? > >> As this is also causing trouble on tegra30-cardhu-a04 the only >> sane solution is to revert it and start over with a proper >> solution for the vexpress problem and a root cause analysis for >> the tegra. > > If someone can tell me which of the timer drivers are relevant for > tegra30-cardhu-a04, I can help fix it. If you want to revert the > original patch first before waiting for a tegra fix, that's okay by > me. It seems the OF_POPULATED flag change spotted something wrong in different drivers and that is a good thing. Thanks for your patch for that. Without putting in question your analysis, we need to stabilize the release, can you send a revert of your patch? Let's try to figure out what is happening and fix the issues in the other drivers for the next cycle. Thanks -- Daniel -- Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog