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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CD7C0C07545 for ; Tue, 24 Oct 2023 16:25:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343651AbjJXQZk (ORCPT ); Tue, 24 Oct 2023 12:25:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38528 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343557AbjJXQZj (ORCPT ); Tue, 24 Oct 2023 12:25:39 -0400 Received: from mo4-p01-ob.smtp.rzone.de (mo4-p01-ob.smtp.rzone.de [81.169.146.166]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6C1AD111; Tue, 24 Oct 2023 09:25:36 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1698164734; cv=none; d=strato.com; s=strato-dkim-0002; b=jFmsKgTNZAZIwUdugGKnmrcnP5auvCuXcRINXCifCaqO2Rxwwh5aTPGR4MBASQ81d/ OHlOQkIEDiM2VJHDCJ0Ar0qRHDGH9jE1tRnCbVRhOL/jkIstiQlwCetHNgbOu46MRfhS nQeYXi4AdGH3sdVqPZN/jL5PeTLM2j7nbVxpFvUeC3tp5VvZy/dec1W9X3TcR2mJPW90 f0gPLZ8R2ZQOb3hcK40vs19NtQhp9nLVsk7gnRTa2KD1uLZ/fafHXOApviEHp8NzM/lC Q6iQdRn4HSFiduvyayKDLraMPVDFDW2Igbbt/lToO01oJ+Hq9xlHwiotzuZZJVsSlh/B nhPg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; t=1698164734; s=strato-dkim-0002; d=strato.com; h=In-Reply-To:References:Message-ID:Subject:Cc:To:From:Date:Cc:Date: From:Subject:Sender; bh=BKuCBeuwdGgUeRuNCbFHWtHrgHiZpvFPcgBdLz2whR4=; b=MKjshxKL2XMbugW1bLA9mN8A0RKMg2KLCu19ikbDuOfgDnchzw7UgMWFUd+C3Skj1/ 5DX/m2puY2yTWVHIMc07WyMuk4JV4aynmNyWZz05eXfkWse/zd86SWqjln2NYNU3Icjk tGyFMIbbJDPuX65tu1o/ba4qjQWiok7CAFYG/M8fgwOjObX4KomI0N+1IU25xDPkIkTY 8jSvz/giiiN6pDAY1cam5yuSt4/q4PpvnZ2y6xL5rUPP/s23Sr/wCxRysvpbu4E2RBEh B9gPEgcD+xi2z+9kYgcMzjwhHt5ElfRoUJq0iXkupIkuf0DG7qyg0xTmIRUGdfK3vbT8 8HYw== ARC-Authentication-Results: i=1; strato.com; arc=none; dkim=none X-RZG-CLASS-ID: mo01 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1698164734; s=strato-dkim-0002; d=gerhold.net; h=In-Reply-To:References:Message-ID:Subject:Cc:To:From:Date:Cc:Date: From:Subject:Sender; bh=BKuCBeuwdGgUeRuNCbFHWtHrgHiZpvFPcgBdLz2whR4=; b=MxgKkMraIPXFbPtFfYbpgzo7AyE6t3/6XtN08BPqKzB4dIDWiByfjTXj4o71jchFO4 xp2PjzC3Ar/4zr1/NugLN+v+LX+lhZ0Rk739Fd0hmD/CGWirt1MQptRjN8mlS/aunEJP YDbDiOtoTZZx41cLh6zYmAL8HMCcLXV5cHqUGt2jDIJKHaOd+oKT8X6nxHJEzGJ2pG5J 06+hUg0ZDoZHt4xZXxU4L8mZp7kiJOwvYUjRbGqe5yeWmFjLN9tH4xt6NE0T39xIx8vA QV2WzNaM0WlSnrqoB9Xy2CCV58Im4HF74ks/GAroHmbWg3jyGlIEoWTjXVKZZrTqvLkz 5WXg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; t=1698164734; s=strato-dkim-0003; d=gerhold.net; h=In-Reply-To:References:Message-ID:Subject:Cc:To:From:Date:Cc:Date: From:Subject:Sender; bh=BKuCBeuwdGgUeRuNCbFHWtHrgHiZpvFPcgBdLz2whR4=; b=2PCEAStkBVaZjcLABSrDuFH8+MKtswPuHybD8FIetqU3T5XlT5mm0KXJESzGBYuJNM 1wOSuHbnT4QEpu196ZCA== X-RZG-AUTH: ":P3gBZUipdd93FF5ZZvYFPugejmSTVR2nRPhVOQ/OcYgojyw4j34+u261EJF5OxJD4peA8Z+P1A==" Received: from gerhold.net by smtp.strato.de (RZmta 49.9.0 DYNA|AUTH) with ESMTPSA id j34a49z9OGPXRmV (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Tue, 24 Oct 2023 18:25:33 +0200 (CEST) Date: Tue, 24 Oct 2023 18:25:28 +0200 From: Stephan Gerhold To: Ulf Hansson Cc: Stephan Gerhold , Viresh Kumar , Andy Gross , Bjorn Andersson , Konrad Dybcio , Ilia Lin , "Rafael J. Wysocki" , Rob Herring , Krzysztof Kozlowski , Conor Dooley , linux-pm@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v2 2/3] cpufreq: qcom-nvmem: Enable virtual power domain devices Message-ID: References: <20231018-msm8909-cpufreq-v2-0-0962df95f654@kernkonzept.com> <20231018-msm8909-cpufreq-v2-2-0962df95f654@kernkonzept.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Tue, Oct 24, 2023 at 06:11:34PM +0200, Ulf Hansson wrote: > On Tue, 24 Oct 2023 at 15:07, Stephan Gerhold > wrote: > > > > On Tue, Oct 24, 2023 at 02:49:32PM +0200, Ulf Hansson wrote: > > > On Tue, 24 Oct 2023 at 14:03, Stephan Gerhold > > > wrote: > > > > > > > > On Thu, Oct 19, 2023 at 01:26:19PM +0200, Ulf Hansson wrote: > > > > > On Thu, 19 Oct 2023 at 12:24, Ulf Hansson wrote: > > > > > > > > > > > > On Wed, 18 Oct 2023 at 10:06, Stephan Gerhold > > > > > > wrote: > > > > > > > > > > > > > > The genpd core caches performance state votes from devices that are > > > > > > > runtime suspended as of commit 3c5a272202c2 ("PM: domains: Improve > > > > > > > runtime PM performance state handling"). They get applied once the > > > > > > > device becomes active again. > > > > > > > > > > > > > > To attach the power domains needed by qcom-cpufreq-nvmem the OPP core > > > > > > > calls genpd_dev_pm_attach_by_id(). This results in "virtual" dummy > > > > > > > devices that use runtime PM only to control the enable and performance > > > > > > > state for the attached power domain. > > > > > > > > > > > > > > However, at the moment nothing ever resumes the virtual devices created > > > > > > > for qcom-cpufreq-nvmem. They remain permanently runtime suspended. This > > > > > > > means that performance state votes made during cpufreq scaling get > > > > > > > always cached and never applied to the hardware. > > > > > > > > > > > > > > Fix this by enabling the devices after attaching them and use > > > > > > > dev_pm_syscore_device() to ensure the power domains also stay on when > > > > > > > going to suspend. Since it supplies the CPU we can never turn it off > > > > > > > from Linux. There are other mechanisms to turn it off when needed, > > > > > > > usually in the RPM firmware (RPMPD) or the cpuidle path (CPR genpd). > > > > > > > > > > > > I believe we discussed using dev_pm_syscore_device() for the previous > > > > > > version. It's not intended to be used for things like the above. > > > > > > > > > > > > Moreover, I was under the impression that it wasn't really needed. In > > > > > > fact, I would think that this actually breaks things for system > > > > > > suspend/resume, as in this case the cpr driver's genpd > > > > > > ->power_on|off() callbacks are no longer getting called due this, > > > > > > which means that the cpr state machine isn't going to be restored > > > > > > properly. Or did I get this wrong? > > > > > > > > > > BTW, if you really need something like the above, the proper way to do > > > > > it would instead be to call device_set_awake_path() for the device. > > > > > > > > > > > > > Unfortunately this does not work correctly. When I use > > > > device_set_awake_path() it does set dev->power.wakeup_path = true. > > > > However, this flag is cleared again in device_prepare() when entering > > > > suspend. To me it looks a bit like wakeup_path is not supposed to be set > > > > directly by drivers? Before and after your commit 8512220c5782 ("PM / > > > > core: Assign the wakeup_path status flag in __device_prepare()") it > > > > seems to be internally bound to device_may_wakeup(). > > > > > > > > It works if I make device_may_wakeup() return true, with > > > > > > > > device_set_wakeup_capable(dev, true); > > > > device_wakeup_enable(dev); > > > > > > > > but that also allows *disabling* the wakeup from sysfs which doesn't > > > > really make sense for the CPU. > > > > > > > > Any ideas? > > > > > > The device_set_awake_path() should be called from a system suspend > > > callback. So you need to add that callback for the cpufreq driver. > > > > > > Sorry, if that wasn't clear. > > > > > > > Hmm, but at the moment I'm calling this on the virtual genpd devices. > > How would it work for them? I don't have a suspend callback for them. > > > > I guess could loop over the virtual devices in the cpufreq driver > > suspend callback, but is my driver suspend callback really guaranteed to > > run before the device_prepare() that clears "wakeup_path" on the virtual > > devices? > > Yes, that's guaranteed. dpm_prepare() (which calls device_prepare()) > is always being executed before dpm_suspend(). > Thanks, I think I understand. Maybe. :-) Just to confirm, I should call device_set_awake_path() for the virtual genpd devices as part of the PM ->suspend() callback? And this will be guaranteed to run after the "prepare" phase but before the "suspend_noirq" phase where the genpd core will check the wakeup flag? Thanks, Stepan