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=-12.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 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 A6766C4727C for ; Tue, 29 Sep 2020 15:18:50 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2335F207C4 for ; Tue, 29 Sep 2020 15:18:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="p5fUDf/T"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="eV+kK2nb" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2335F207C4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=ylGN+VlugfZ7yfEXnn8aUYiy6BYLjbFQOXIR0VDbfk4=; b=p5fUDf/TowtSdrEEbsfFum5ts 3Q2knBc+pD4r9iSBsfmEvrnA8e+VLQ8ckZj9GErYRvdb0cvLagV+x1SeeqXfabYYfVt+uzdcJ+1bn qJxq5brUjiOILxuqTm5bXiTFvw1QulMosI+zBHQtaT5sfcUAsuY4mnRWb3qCG93R/blKzK79HIgV0 BItxC6E4zykZAzK4q8XGW3qR4iw01kqG923N2jbQ9vUsuzlJzFanvuyKgBEtILKoKhpmE8t6Ogyx6 bdoMfXSUCoR952Zfa6PlqQYXjZiForZ/CVrt1USjZOyZJteNlIeUdLU9PBMny8cjDFpTItHcMcaXO turtQ8qoQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kNHNn-0001K3-PL; Tue, 29 Sep 2020 15:17:35 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kNHNk-0001JC-Fp for linux-arm-kernel@lists.infradead.org; Tue, 29 Sep 2020 15:17:33 +0000 Received: from archlinux (cpc149474-cmbg20-2-0-cust94.5-4.cable.virginm.net [82.4.196.95]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8F72C20773; Tue, 29 Sep 2020 15:17:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601392650; bh=Tg4e0HkMtzHqfzx+B1Jd5XPOo5wQ0MptzkCySYDjXnI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=eV+kK2nbloNFXchh95Pr8vkanZ+1W8f1vO/xaD/arhLCBm9SrAHwlRjFRNSdlMeNR kYkA0B4Q9o4E6kuYLYm5aGxGY7zR8l7MzfBgIS0EAVMVLm5rXqAJ02DdrxxRyNgBkW Rmh2raGt6kXHnIhu98S2zKLOsF1ab00IUy7ymcWE= Date: Tue, 29 Sep 2020 16:17:25 +0100 From: Jonathan Cameron To: Ulf Hansson Subject: Re: [RESEND PATCH v2] iio: adc: stm32-adc: fix runtime autosuspend delay when slow polling Message-ID: <20200929161725.7c8e20a8@archlinux> In-Reply-To: References: <1593615328-5180-1-git-send-email-fabrice.gasnier@st.com> <045e9e34-f1e0-087b-bc5b-44440db6be27@st.com> <20200926161732.72af96e3@archlinux> X-Mailer: Claws Mail 3.17.6 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200929_111732_737539_60895CC6 X-CRM114-Status: GOOD ( 45.37 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: olivier.moysan@st.com, Alexandre Torgue , linux-iio@vger.kernel.org, "Rafael J. Wysocki" , "Rafael J. Wysocki" , Linux Kernel Mailing List , Maxime Coquelin , Fabrice Gasnier , linux-stm32@st-md-mailman.stormreply.com, Linux ARM Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, 28 Sep 2020 13:23:11 +0200 Ulf Hansson wrote: > Jonathan, Fabrice, > > On Sat, 26 Sep 2020 at 17:17, Jonathan Cameron wrote: > > > > On Wed, 16 Sep 2020 12:28:00 +0200 > > Fabrice Gasnier wrote: > > > > > On 7/1/20 4:55 PM, Fabrice Gasnier wrote: > > > > When the ADC is runtime suspended and starting a conversion, the stm32-adc > > > > driver calls pm_runtime_get_sync() that gets cascaded to the parent > > > > (e.g. runtime resume of stm32-adc-core driver). This also kicks the > > > > autosuspend delay (e.g. 2s) of the parent. > > > > Once the ADC is active, calling pm_runtime_get_sync() again (upon a new > > > > capture) won't kick the autosuspend delay for the parent (stm32-adc-core > > > > driver) as already active. > > > > > > > > Currently, this makes the stm32-adc-core driver go in suspend state > > > > every 2s when doing slow polling. As an example, doing a capture, e.g. > > > > cat in_voltageY_raw at a 0.2s rate, the auto suspend delay for the parent > > > > isn't refreshed. Once it expires, the parent immediately falls into > > > > runtime suspended state, in between two captures, as soon as the child > > > > driver falls into runtime suspend state: > > > > - e.g. after 2s, + child calls pm_runtime_put_autosuspend() + 100ms > > > > autosuspend delay of the child. > > > > - stm32-adc-core switches off regulators, clocks and so on. > > > > - They get switched on back again 100ms later in this example (at 2.2s). > > > > > > > > So, use runtime_idle() callback in stm32-adc-core driver to call > > > > pm_runtime_mark_last_busy() for the parent driver (stm32-adc-core), > > > > to avoid this. > > > > > > > > Fixes: 9bdbb1139ca1 ("iio: adc: stm32-adc: add power management support") > > > > > > > > Signed-off-by: Fabrice Gasnier > > > > --- > > > > Changes in v2: > > > > - Use runtime_idle callback in stm32-adc-core driver, instead of refreshing > > > > last_busy from the child (for the parent) at many place. Initial patch v1 > > > > looked like "somewhat adhoc solution" as commented by Jonathan. > > > > > > Hi all, > > > > > > Gentle reminder for this patch. Earlier discussions on it were as per > > > [1] and [2]. > > > > > > Ideally, Jonathan was looking for an ack from Rafael on this patch. > > > This is a long pending issue. I'd like to progress on this. > > > > > > [1] https://patchwork.kernel.org/patch/11349841/ > > > [2] https://lkml.org/lkml/2020/6/11/279 > > > > Fabrice, I think this one has sat waiting for inputs for > > too long. Hence I'm going to take a slight gamble that you are correct > > on doing the fix this way (I'm reasonably convinced) > > My apologies for the huge and unacceptable delay. I have re-started > looking at this several times, but just never got the point of writing > a proper reply. Let me do this now, better late than never I guess. > > In general, I think this problem (nicely described by Fabrice), should > be solved in the runtime PM core, without having to involve drivers > for parents/childs. I have looked into that, but I don't have a patch > to propose, at least not yet. > > FYI, I have also stumbled over the same problem, for a card controller > (parent), serving both sd and memstick cards. For that case, we simply > decided to skip using autosuspend for the child devices (represented > by an sd host and a memstick host), not optimal, but there were other > reasons why we decided for this approach as well. > > That said, I also think the solution proposed in $subject patch, which > uses the ->runtime_idle() callback for the parent is perfectly fine, > at least until we have figured out something that can replace it. > > > > > Applied to the fixes-togreg branch of iio.git. > > It won't go in for 5.9 now, so we have a bit of time for any last > > minute comments. > > Feel free to add: > > Reviewed-by: Ulf Hansson Thanks and added. Jonathan > > Kind regards > Uffe > > > > > Thanks, > > > > Jonathan > > > > > > > > Please advise, > > > Thanks in advance, > > > Fabrice > > > > > > > --- > > > > drivers/iio/adc/stm32-adc-core.c | 9 ++++++++- > > > > 1 file changed, 8 insertions(+), 1 deletion(-) > > > > > > > > diff --git a/drivers/iio/adc/stm32-adc-core.c b/drivers/iio/adc/stm32-adc-core.c > > > > index 0e2068e..3586369 100644 > > > > --- a/drivers/iio/adc/stm32-adc-core.c > > > > +++ b/drivers/iio/adc/stm32-adc-core.c > > > > @@ -794,6 +794,13 @@ static int stm32_adc_core_runtime_resume(struct device *dev) > > > > { > > > > return stm32_adc_core_hw_start(dev); > > > > } > > > > + > > > > +static int stm32_adc_core_runtime_idle(struct device *dev) > > > > +{ > > > > + pm_runtime_mark_last_busy(dev); > > > > + > > > > + return 0; > > > > +} > > > > #endif > > > > > > > > static const struct dev_pm_ops stm32_adc_core_pm_ops = { > > > > @@ -801,7 +808,7 @@ static const struct dev_pm_ops stm32_adc_core_pm_ops = { > > > > pm_runtime_force_resume) > > > > SET_RUNTIME_PM_OPS(stm32_adc_core_runtime_suspend, > > > > stm32_adc_core_runtime_resume, > > > > - NULL) > > > > + stm32_adc_core_runtime_idle) > > > > }; > > > > > > > > static const struct stm32_adc_priv_cfg stm32f4_adc_priv_cfg = { > > > > > > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel