From: "Rafael J. Wysocki" <rjw@rjwysocki.net> To: Pavel Machek <pavel@ucw.cz> Cc: Florian Fainelli <f.fainelli@gmail.com>, linux-kernel@vger.kernel.org, Alexandre Belloni <alexandre.belloni@free-electrons.com>, "Rafael J. Wysocki" <rafael@kernel.org>, Ulf Hansson <ulf.hansson@linaro.org>, Daniel Lezcano <daniel.lezcano@linaro.org>, linux-pm <linux-pm@vger.kernel.org>, Thibaud Cornic <thibaud_cornic@sigmadesigns.com>, JB <jb_lescher@sigmadesigns.com>, Mason <slash.tmp@free.fr>, Kevin Hilman <khilman@kernel.org>, Linux ARM <linux-arm-kernel@lists.infradead.org> Subject: Re: [RFC 1/2] PM / suspend: Add platform_suspend_target_state() Date: Sun, 16 Jul 2017 12:28:40 +0200 [thread overview] Message-ID: <5290346.YItt1Jp12B@aspire.rjw.lan> (raw) In-Reply-To: <20170706031750.GA12954@xo-6d-61-c0.localdomain> On Thursday, July 06, 2017 05:17:50 AM Pavel Machek wrote: > On Sun 2017-07-16 01:29:57, Rafael J. Wysocki wrote: > > On Saturday, July 15, 2017 06:46:26 PM Pavel Machek wrote: > > > Hi! > > > > > > > > > I had an idea of using an enum type encompassing all of the power states > > > > > > defined for various platforms and serving both as a registry (to ensure the > > > > > > uniqueness of the values assigned to the states) and a common ground > > > > > > between platforms and drivers. > > > > > > > > > > > > Something like: > > > > > > > > > > > > enum platform_target_state { > > > > > > PLATFORM_STATE_UNKNOWN = -1, > > > > > > PLATFORM_STATE_WORKING = 0, > > > > > > PLATFORM_STATE_ACPI_S1, > > > > > > PLATFORM_STATE_ACPI_S2, > > > > > > PLATFORM_STATE_ACPI_S3, > > > > > > PLATFORM_STATE_MY_BOARD_1_GATE_CLOCKS, > > > > > > PLATFORM_STATE_MY_BOARD_1_GATE_POWER, > > > > > > PLATFORM_STATE_ANOTHER_BOARD_DO_CRAZY_STUFF, > > > > > > ... > > > > > > }; > > > > > > > > > > > > and define ->target_state to return a value of this type. > > > > > > > > > > > > Then, if a driver sees one of these and recognizes that value, it should > > > > > > know exactly what to do. > > > > > > > > > > Remind me why this is good idea? > > > > > > > > Because there are drivers that need to do specific things during > > > > suspend on a specific board when it goes into a specific state as a > > > > whole. > > > > > > We have seen driver that cares about voltage to his device being > > > lost. That's reasonable. > > > > > > Inquiring what the platform target state is... is not. > > > > So why exactly isn't it reasonable? > > > > Please use technical arguments. Saying that something is wrong without > > explaining the problem you see with it isn't particulatly useful in technical > > discussions. > > Deep in your heart, you should know that having enum listing all the platforms linux > runs on is a very bad idea. Even so, if I'm unable to explain to people why this is a bad idea in technical terms, that doesn't mean too much. I actually noticed an issue with the approach that I missed before, see my last reply to Florian. > Anyway, there are better solutions, regulator framework already knows if given rail > will be powered off or not, and their driver already knows if they are going > suspend/standby. They just need to use existing interfaces. So they need to know what has been passed to suspend_devices_and_enter() anyway and currently there's no interface for that. That actually is the source of the whole issue. Thanks, Rafael
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From: rjw@rjwysocki.net (Rafael J. Wysocki) To: linux-arm-kernel@lists.infradead.org Subject: [RFC 1/2] PM / suspend: Add platform_suspend_target_state() Date: Sun, 16 Jul 2017 12:28:40 +0200 [thread overview] Message-ID: <5290346.YItt1Jp12B@aspire.rjw.lan> (raw) In-Reply-To: <20170706031750.GA12954@xo-6d-61-c0.localdomain> On Thursday, July 06, 2017 05:17:50 AM Pavel Machek wrote: > On Sun 2017-07-16 01:29:57, Rafael J. Wysocki wrote: > > On Saturday, July 15, 2017 06:46:26 PM Pavel Machek wrote: > > > Hi! > > > > > > > > > I had an idea of using an enum type encompassing all of the power states > > > > > > defined for various platforms and serving both as a registry (to ensure the > > > > > > uniqueness of the values assigned to the states) and a common ground > > > > > > between platforms and drivers. > > > > > > > > > > > > Something like: > > > > > > > > > > > > enum platform_target_state { > > > > > > PLATFORM_STATE_UNKNOWN = -1, > > > > > > PLATFORM_STATE_WORKING = 0, > > > > > > PLATFORM_STATE_ACPI_S1, > > > > > > PLATFORM_STATE_ACPI_S2, > > > > > > PLATFORM_STATE_ACPI_S3, > > > > > > PLATFORM_STATE_MY_BOARD_1_GATE_CLOCKS, > > > > > > PLATFORM_STATE_MY_BOARD_1_GATE_POWER, > > > > > > PLATFORM_STATE_ANOTHER_BOARD_DO_CRAZY_STUFF, > > > > > > ... > > > > > > }; > > > > > > > > > > > > and define ->target_state to return a value of this type. > > > > > > > > > > > > Then, if a driver sees one of these and recognizes that value, it should > > > > > > know exactly what to do. > > > > > > > > > > Remind me why this is good idea? > > > > > > > > Because there are drivers that need to do specific things during > > > > suspend on a specific board when it goes into a specific state as a > > > > whole. > > > > > > We have seen driver that cares about voltage to his device being > > > lost. That's reasonable. > > > > > > Inquiring what the platform target state is... is not. > > > > So why exactly isn't it reasonable? > > > > Please use technical arguments. Saying that something is wrong without > > explaining the problem you see with it isn't particulatly useful in technical > > discussions. > > Deep in your heart, you should know that having enum listing all the platforms linux > runs on is a very bad idea. Even so, if I'm unable to explain to people why this is a bad idea in technical terms, that doesn't mean too much. I actually noticed an issue with the approach that I missed before, see my last reply to Florian. > Anyway, there are better solutions, regulator framework already knows if given rail > will be powered off or not, and their driver already knows if they are going > suspend/standby. They just need to use existing interfaces. So they need to know what has been passed to suspend_devices_and_enter() anyway and currently there's no interface for that. That actually is the source of the whole issue. Thanks, Rafael
next prev parent reply other threads:[~2017-07-16 10:36 UTC|newest] Thread overview: 118+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-06-09 15:20 Drivers taking different actions depending on sleep state Mason 2017-06-09 15:20 ` Mason 2017-06-09 16:27 ` Mason 2017-06-09 16:27 ` Mason 2017-06-09 21:30 ` Pavel Machek 2017-06-09 21:30 ` Pavel Machek 2017-06-10 9:16 ` Mason 2017-06-10 9:16 ` Mason 2017-06-09 22:05 ` Florian Fainelli 2017-06-09 22:05 ` Florian Fainelli 2017-06-09 22:53 ` Rafael J. Wysocki 2017-06-09 22:53 ` Rafael J. Wysocki 2017-06-21 21:16 ` Florian Fainelli 2017-06-21 21:16 ` Florian Fainelli 2017-06-21 21:59 ` Rafael J. Wysocki 2017-06-21 21:59 ` Rafael J. Wysocki 2017-06-21 22:48 ` Florian Fainelli 2017-06-21 22:48 ` Florian Fainelli 2017-06-21 22:57 ` Rafael J. Wysocki 2017-06-21 22:57 ` Rafael J. Wysocki 2017-06-21 23:55 ` Florian Fainelli 2017-06-21 23:55 ` Florian Fainelli 2017-06-22 0:03 ` Rafael J. Wysocki 2017-06-22 0:03 ` Rafael J. Wysocki 2017-06-22 15:18 ` Florian Fainelli 2017-06-22 15:18 ` Florian Fainelli 2017-06-22 16:09 ` Rafael J. Wysocki 2017-06-22 16:09 ` Rafael J. Wysocki 2017-06-22 8:51 ` Alexandre Belloni 2017-06-22 8:51 ` Alexandre Belloni 2017-06-22 16:00 ` Rafael J. Wysocki 2017-06-22 16:00 ` Rafael J. Wysocki 2017-06-23 1:08 ` [RFC 0/2] PM / suspend: Add platform_suspend_target_state() Florian Fainelli 2017-06-23 1:08 ` Florian Fainelli 2017-06-23 1:08 ` [RFC 1/2] " Florian Fainelli 2017-06-23 1:08 ` Florian Fainelli 2017-06-29 23:00 ` Rafael J. Wysocki 2017-06-29 23:00 ` Rafael J. Wysocki 2017-07-12 18:08 ` Florian Fainelli 2017-07-12 18:08 ` Florian Fainelli 2017-07-14 22:16 ` Rafael J. Wysocki 2017-07-14 22:16 ` Rafael J. Wysocki 2017-07-15 6:28 ` Pavel Machek 2017-07-15 6:28 ` Pavel Machek 2017-07-15 12:17 ` Rafael J. Wysocki 2017-07-15 12:17 ` Rafael J. Wysocki 2017-07-15 16:46 ` Pavel Machek 2017-07-15 16:46 ` Pavel Machek 2017-07-15 17:20 ` Florian Fainelli 2017-07-15 17:20 ` Florian Fainelli 2017-07-15 18:33 ` Alexandre Belloni 2017-07-15 18:33 ` Alexandre Belloni 2017-07-06 3:18 ` Pavel Machek 2017-07-06 3:18 ` Pavel Machek 2017-07-16 13:41 ` Alexandre Belloni 2017-07-16 13:41 ` Alexandre Belloni 2017-07-16 15:35 ` Florian Fainelli 2017-07-16 15:35 ` Florian Fainelli 2017-07-15 23:24 ` Rafael J. Wysocki 2017-07-15 23:24 ` Rafael J. Wysocki 2017-07-15 23:34 ` Mason 2017-07-15 23:34 ` Mason 2017-07-15 23:38 ` Rafael J. Wysocki 2017-07-15 23:38 ` Rafael J. Wysocki 2017-07-16 2:36 ` Florian Fainelli 2017-07-16 2:36 ` Florian Fainelli 2017-07-16 10:22 ` Rafael J. Wysocki 2017-07-16 10:22 ` Rafael J. Wysocki 2017-07-16 13:38 ` Alexandre Belloni 2017-07-16 13:38 ` Alexandre Belloni 2017-07-16 18:24 ` Pavel Machek 2017-07-16 18:24 ` Pavel Machek 2017-07-16 15:41 ` Florian Fainelli 2017-07-16 15:41 ` Florian Fainelli 2017-07-15 23:29 ` Rafael J. Wysocki 2017-07-15 23:29 ` Rafael J. Wysocki 2017-07-06 3:17 ` Pavel Machek 2017-07-06 3:17 ` Pavel Machek 2017-07-16 10:28 ` Rafael J. Wysocki [this message] 2017-07-16 10:28 ` Rafael J. Wysocki 2017-07-16 18:22 ` Pavel Machek 2017-07-16 18:22 ` Pavel Machek 2017-06-23 1:08 ` [RFC 2/2] soc: bcm: brcmstb: PM: Implement target_state callback Florian Fainelli 2017-06-23 1:08 ` Florian Fainelli 2017-06-29 23:04 ` Rafael J. Wysocki 2017-06-29 23:04 ` Rafael J. Wysocki 2017-07-16 2:36 ` [PATCH 0/2] PM / suspend: Add platform_suspend_target_state() Florian Fainelli 2017-07-16 2:36 ` Florian Fainelli 2017-07-16 2:36 ` [PATCH 1/2] " Florian Fainelli 2017-07-16 2:36 ` Florian Fainelli 2017-07-06 3:18 ` Pavel Machek 2017-07-06 3:18 ` Pavel Machek 2017-07-16 15:41 ` Florian Fainelli 2017-07-16 15:41 ` Florian Fainelli 2017-07-16 10:30 ` Rafael J. Wysocki 2017-07-16 10:30 ` Rafael J. Wysocki 2017-07-16 2:36 ` [PATCH 2/2] soc: bcm: brcmstb: PM: Implement target_state callback Florian Fainelli 2017-07-16 2:36 ` Florian Fainelli 2017-07-17 20:06 ` [PATCH v2] PM / suspend: Add suspend_target_state() Florian Fainelli 2017-07-17 20:06 ` Florian Fainelli 2017-07-17 20:16 ` Pavel Machek 2017-07-17 20:16 ` Pavel Machek 2017-07-17 21:03 ` Rafael J. Wysocki 2017-07-17 21:03 ` Rafael J. Wysocki 2017-07-17 21:21 ` Florian Fainelli 2017-07-17 21:21 ` Florian Fainelli 2017-07-20 8:03 ` Pavel Machek 2017-07-20 8:03 ` Pavel Machek 2017-07-17 22:10 ` [PATCH v3] PM / suspend: Export pm_suspend_target_state Florian Fainelli 2017-07-17 22:10 ` Florian Fainelli 2017-07-17 23:24 ` Rafael J. Wysocki 2017-07-17 23:24 ` Rafael J. Wysocki 2017-07-18 0:19 ` [PATCH v4] " Florian Fainelli 2017-07-18 0:19 ` Florian Fainelli 2017-07-24 20:55 ` Rafael J. Wysocki 2017-07-24 20:55 ` Rafael J. Wysocki 2017-07-13 12:03 ` Drivers taking different actions depending on sleep state Pavel Machek 2017-07-13 12:03 ` Pavel Machek
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