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 F0B0EC4167B for ; Tue, 31 Oct 2023 09:48:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229656AbjJaJsU (ORCPT ); Tue, 31 Oct 2023 05:48:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39740 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230264AbjJaJsT (ORCPT ); Tue, 31 Oct 2023 05:48:19 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2557ED8; Tue, 31 Oct 2023 02:48:17 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0E787C433C8; Tue, 31 Oct 2023 09:48:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1698745696; bh=sM1Wv4trc5rYZHu5HPyjKmqhgM0mXr3pLbPOECiZojA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=BW0jS6/LBpKeo8eSNpHnM0lI92BdOehwUWDCNEqNAwtKgSgNv49mXuO0AYlgO8v3M H7b5YRXO1CESFmn6lcM8v9y1DLYWYPDuRhwMpfS0ZfmMm7gwqkv6ALrjoR+0w5nj72 KS2x/XljH6UXfgQmWSQaUn1mHjNIHlimwKpCRYyM= Date: Tue, 31 Oct 2023 10:48:13 +0100 From: Greg KH To: Guan-Yu Lin Cc: rafael@kernel.org, len.brown@intel.com, pavel@ucw.cz, stern@rowland.harvard.edu, heikki.krogerus@linux.intel.com, mkl@pengutronix.de, hadess@hadess.net, mailhol.vincent@wanadoo.fr, ivan.orlov0322@gmail.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, pumahsu@google.com, raychi@google.com, albertccwang@google.com Subject: Re: [PATCH] rpm: pm: enable PM_RPM_EXCEPTION config flag Message-ID: <2023103133-kelp-copartner-8e9c@gregkh> References: <20231031093921.755204-1-guanyulin@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231031093921.755204-1-guanyulin@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Tue, Oct 31, 2023 at 05:38:55PM +0800, Guan-Yu Lin wrote: > Introducing PM_RPM_EXCEPTION config flag, which may alter the priority > between system power management and runtime power management. In > suspend-to-idle flow, PM core will suspend all devices to avoid device > interact with the system. However, chances are devices might be used by > other systems rather than a single system. In this case, PM core shouldn't > suspend the devices. One may use PM_RPM_EXCEPTION config flag to mark > such exception, and determine the power state of a device with runtime > power management rather than system power management. > > Signed-off-by: Guan-Yu Lin > --- > drivers/usb/core/generic.c | 6 ++++++ > drivers/usb/core/usb.h | 16 ++++++++++++++++ > kernel/power/Kconfig | 8 ++++++++ > 3 files changed, 30 insertions(+) > > diff --git a/drivers/usb/core/generic.c b/drivers/usb/core/generic.c > index 740342a2812a..bb0dfcfc9764 100644 > --- a/drivers/usb/core/generic.c > +++ b/drivers/usb/core/generic.c > @@ -266,6 +266,9 @@ int usb_generic_driver_suspend(struct usb_device *udev, pm_message_t msg) > { > int rc; > > + if (usb_runtime_pm_exception(udev)) > + return 0; > + > /* Normal USB devices suspend through their upstream port. > * Root hubs don't have upstream ports to suspend, > * so we have to shut down their downstream HC-to-USB > @@ -294,6 +297,9 @@ int usb_generic_driver_resume(struct usb_device *udev, pm_message_t msg) > { > int rc; > > + if (usb_runtime_pm_exception(udev)) > + return 0; > + > /* Normal USB devices resume/reset through their upstream port. > * Root hubs don't have upstream ports to resume or reset, > * so we have to start up their downstream HC-to-USB > diff --git a/drivers/usb/core/usb.h b/drivers/usb/core/usb.h > index 60363153fc3f..14a054f814a2 100644 > --- a/drivers/usb/core/usb.h > +++ b/drivers/usb/core/usb.h > @@ -90,6 +90,22 @@ extern void usb_major_cleanup(void); > extern int usb_device_supports_lpm(struct usb_device *udev); > extern int usb_port_disable(struct usb_device *udev); > > +#ifdef CONFIG_PM_RPM_EXCEPTION > + > +static inline int usb_runtime_pm_exception(struct usb_device *udev) > +{ > + return atomic_read(&udev->dev.power.usage_count); > +} > + > +#else > + > +static inline int usb_runtime_pm_exception(struct usb_device *udev) > +{ > + return 0; > +} > + > +#endif > + > #ifdef CONFIG_PM > > extern int usb_suspend(struct device *dev, pm_message_t msg); > diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig > index 4b31629c5be4..beba7a0f3947 100644 > --- a/kernel/power/Kconfig > +++ b/kernel/power/Kconfig > @@ -193,6 +193,14 @@ config PM > responsible for the actual handling of device suspend requests and > wake-up events. > > +config PM_RPM_EXCEPTION > + bool "Prioritize Runtime Power Management more than Power Management" > + default n The default is always 'n' so no need to specify it. > + help > + Provides a way to prioritize Runtime Power Management more than Power > + Management. This way system can suspnd with maintaining specific > + components in operation. This really doesn't give me a good description of why someone would ever want to enable this at all. And why does this have to be a build option? That feels very heavy, why not make it changable at runtime? If this is a build option, how are you going to get all the distros and all of the Android/ChromeOS systems in the world to enable it? thanks, greg k-h