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 E4E27C433FE for ; Sat, 7 May 2022 07:31:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1445985AbiEGHfR (ORCPT ); Sat, 7 May 2022 03:35:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40138 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1386097AbiEGHfQ (ORCPT ); Sat, 7 May 2022 03:35:16 -0400 Received: from relay9-d.mail.gandi.net (relay9-d.mail.gandi.net [217.70.183.199]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 19E2E4579C; Sat, 7 May 2022 00:31:28 -0700 (PDT) Received: (Authenticated sender: alexandre.belloni@bootlin.com) by mail.gandi.net (Postfix) with ESMTPSA id B50DEFF803; Sat, 7 May 2022 07:31:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1651908687; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Yj76RWm4PAng0nU1sLIhfTSnacWzd2+e9h4pJ1GF1LQ=; b=SU+FT2mtyoLI+ePai5KrBxZwbcPn5dyEgTSZmUiPaPgi8JvwLnvTo+Yfr7M7imJmOw1FFi +Tpzh9lhyJHW9LGwcDQx3MNmik6H3igk7l4PphypmdMLFnSaU1jxz7ce9sDSiC1BmOJiP3 br4hzudrrfzoFEeypRwJO9Pg2jhUl63irsaUr8gB59UYh/BDEKRycJSP5HEG5CV9Yc54Tk 6Z+mCLRQis/UG1OyCpx+//AlGJ7D1qGboVu/RV/KJ5GiuDG3rTbdfuh6nemfX5t+E5GScD dd+n9LilWKUhQcsYB4Aqp17byP8FjJ4MKRi/Y+VJeRwukYvb5G5CP466K7hWxg== Date: Sat, 7 May 2022 09:31:26 +0200 From: Alexandre Belloni To: Zhang Rui Cc: rjw@rjwysocki.net, kvalo@kernel.org, linux-pm@vger.kernel.org, linux-acpi@vger.kernel.org, linux-rtc@vger.kernel.org, linux-wireless@vger.kernel.org, daniel.lezcano@linaro.org, merez@codeaurora.org, mat.jonczyk@o2.pl, sumeet.r.pawnikar@intel.com, len.brown@intel.com Subject: Re: [PATCH 7/7] rtc: cmos: Add suspend/resume endurance testing hook Message-ID: References: <20220505015814.3727692-1-rui.zhang@intel.com> <20220505015814.3727692-8-rui.zhang@intel.com> <320773e042a538782411f4db838bdc70a1b0851b.camel@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <320773e042a538782411f4db838bdc70a1b0851b.camel@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On 07/05/2022 10:00:40+0800, Zhang Rui wrote: > Hi, Alexandre, > > Thanks for reviewing the patch. > > On Fri, 2022-05-06 at 23:46 +0200, Alexandre Belloni wrote: > > Hello, > > > > I assume I can ignore this patch as this seems to be only for testing > > The main purpose of this patch is for automate testing. > But this doesn't mean it cannot be part of upstream code, right? > > > I'm not even sure why this is needed as this completely breaks > > setting > > the alarm time. > > Or overrides the alarm time, :) > > People rely on the rtc alarm in the automated suspend stress test, > which suspend and resume the system for over 1000 iterations. > As I mentioned in the cover letter of this patch series, if the system > suspend time varies from under 1 second to over 60 seconds, how to > alarm the RTC before suspend? > This feature is critical in this scenario. > > Plus, the current solution is transparent to people who don't known/use > this "rtc_wake_override_sec" parameter. And for people who use this, > they should know that the previous armed RTC alarm will be overrode > whenever a system suspend is triggered. I can add a message when the > parameter is set, if needed. > It is not transparent, if I read your patch properly, this breaks wakeup for everyone... > > On 05/05/2022 09:58:14+0800, Zhang Rui wrote: > > > +static int cmos_pm_notify(struct notifier_block *nb, unsigned long > > > mode, void *_unused) > > > +{ > > > + struct cmos_rtc *cmos = container_of(nb, struct cmos_rtc, > > > pm_nb); > > > + struct rtc_device *rtc = cmos->rtc; > > > + unsigned long now; > > > + struct rtc_wkalrm alm; > > > + > > > + if (rtc_wake_override_sec == 0) > > > + return NOTIFY_OK; > > > + > > > + switch (mode) { > > > + case PM_SUSPEND_PREPARE: > > > + /* > > > + * Cancel the timer to make sure it won't fire > > > + * before rtc is rearmed later. > > > + */ > > > + rtc_timer_cancel(rtc, &rtc->aie_timer); > > > + break; > > > + case PM_SUSPEND_LATE: > > > + if (rtc_read_time(rtc, &alm.time)) > > > + return NOTIFY_BAD; > > > + > > > + now = rtc_tm_to_time64(&alm.time); > > > + memset(&alm, 0, sizeof(alm)); > > > + rtc_time64_to_tm(now + rtc_wake_override_sec, > > > &alm.time); > > > + alm.enabled = true; > > > + if (rtc_set_alarm(rtc, &alm)) > > > + return NOTIFY_BAD; ... because if rtc_wake_override_sec is not set, this sets the alarm to now which is the current RTC time, ensuring the alarm will never trigger. -- Alexandre Belloni, co-owner and COO, Bootlin Embedded Linux and Kernel engineering https://bootlin.com