From: Mark Rutland <mark.rutland@arm.com> To: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Sudeep Holla <sudeep.holla@arm.com>, Pavel Machek <pavel@ucw.cz>, Geert Uytterhoeven <geert+renesas@glider.be>, Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>, Lina Iyer <lina.iyer@linaro.org>, John Stultz <john.stultz@linaro.org>, Thomas Gleixner <tglx@linutronix.de>, "Rafael J . Wysocki" <rjw@rjwysocki.net>, Len Brown <len.brown@intel.com>, Rob Herring <robh+dt@kernel.org>, Magnus Damm <magnus.damm@gmail.com>, "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>, "linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org>, Linux-Renesas <linux-renesas-soc@vger.kernel.org>, Linux PM list <linux-pm@vger.kernel.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org> Subject: Re: [PATCH/RFC 3/6] drivers: firmware: psci: Implement shallow suspend mode Date: Tue, 21 Feb 2017 18:18:49 +0000 [thread overview] Message-ID: <20170221181849.GG8605@leverpostej> (raw) In-Reply-To: <CAMuHMdX_pot+=rJfY1Kor4gYD4CgBYivngzCLwV36LELx+AA5Q@mail.gmail.com> Hi, On Tue, Feb 21, 2017 at 07:06:04PM +0100, Geert Uytterhoeven wrote: > On Tue, Feb 21, 2017 at 6:20 PM, Mark Rutland <mark.rutland@arm.com> wrote: > > On Tue, Feb 21, 2017 at 05:32:50PM +0100, Geert Uytterhoeven wrote: > >> How can Linux know if using "deep" suspend will allow to wake-up the system > >> according to configured wake-up sources, or not? > > > > My understanding is that if a device can wake the system from > > PSCI_SYSTEM_SUSPEND, it should be described in the DT as a wakeup source > > [1]. So we should be able to determine the set of devices which can wake > > the system from a suspend. We shouldn't assume that other devices can > > (though I don't precisely what we do currently). > > > > Otherwise, where PSCI_CPU_SUSPEND, we'd expect that most devices > > (barring cpu-local timers) can wake up CPUs, and hence the system, by > > raising an interrupt. > > > [1] Documentation/devicetree/bindings/power/wakeup-source.txt > > "wakeup-source" in DT is used as a mix of hardware description and software > policy. E.g. some keys on a keyboard may have it, others don't, while there's > not always a technical reason for that. > > Also, it doesn't specify from which suspend state it can wake-up. Joy. If we need to do something here, we should clarify the semantics of wakeup-source and/or introduce a property which is explicitly for the purpose of expressing HW capability to wake up from a specific power state. > On top of that, the Linux PM subsystem allows to configure wakeup by writing > "enabled" to a device's "wakeup" file in sysfs. Or you can use ethtool for > Wake-on-LAN. Sure; userspace can always do something silly here. As I mentioned in my other reply, we could/should add an interface to allow userspace to determine if it has a guaranteed wakeup, which would allow us to do the right thing. Thanks, Mark.
WARNING: multiple messages have this Message-ID (diff)
From: mark.rutland@arm.com (Mark Rutland) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH/RFC 3/6] drivers: firmware: psci: Implement shallow suspend mode Date: Tue, 21 Feb 2017 18:18:49 +0000 [thread overview] Message-ID: <20170221181849.GG8605@leverpostej> (raw) In-Reply-To: <CAMuHMdX_pot+=rJfY1Kor4gYD4CgBYivngzCLwV36LELx+AA5Q@mail.gmail.com> Hi, On Tue, Feb 21, 2017 at 07:06:04PM +0100, Geert Uytterhoeven wrote: > On Tue, Feb 21, 2017 at 6:20 PM, Mark Rutland <mark.rutland@arm.com> wrote: > > On Tue, Feb 21, 2017 at 05:32:50PM +0100, Geert Uytterhoeven wrote: > >> How can Linux know if using "deep" suspend will allow to wake-up the system > >> according to configured wake-up sources, or not? > > > > My understanding is that if a device can wake the system from > > PSCI_SYSTEM_SUSPEND, it should be described in the DT as a wakeup source > > [1]. So we should be able to determine the set of devices which can wake > > the system from a suspend. We shouldn't assume that other devices can > > (though I don't precisely what we do currently). > > > > Otherwise, where PSCI_CPU_SUSPEND, we'd expect that most devices > > (barring cpu-local timers) can wake up CPUs, and hence the system, by > > raising an interrupt. > > > [1] Documentation/devicetree/bindings/power/wakeup-source.txt > > "wakeup-source" in DT is used as a mix of hardware description and software > policy. E.g. some keys on a keyboard may have it, others don't, while there's > not always a technical reason for that. > > Also, it doesn't specify from which suspend state it can wake-up. Joy. If we need to do something here, we should clarify the semantics of wakeup-source and/or introduce a property which is explicitly for the purpose of expressing HW capability to wake up from a specific power state. > On top of that, the Linux PM subsystem allows to configure wakeup by writing > "enabled" to a device's "wakeup" file in sysfs. Or you can use ethtool for > Wake-on-LAN. Sure; userspace can always do something silly here. As I mentioned in my other reply, we could/should add an interface to allow userspace to determine if it has a guaranteed wakeup, which would allow us to do the right thing. Thanks, Mark.
next prev parent reply other threads:[~2017-02-21 18:19 UTC|newest] Thread overview: 145+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-02-20 20:33 [PATCH/RFC 0/6] PSCI: Fix non-PMIC wake-up if SYSTEM_SUSPEND cuts power Geert Uytterhoeven 2017-02-20 20:33 ` Geert Uytterhoeven 2017-02-20 20:33 ` [PATCH/RFC 1/6] alarmtimer: Postpone wake-up source registration until really available Geert Uytterhoeven 2017-02-20 20:33 ` Geert Uytterhoeven 2017-02-20 20:33 ` [PATCH/RFC 2/6] PM / Wakeup: Add wakeup_source_available() Geert Uytterhoeven 2017-02-20 20:33 ` Geert Uytterhoeven 2017-02-20 20:33 ` [PATCH/RFC 3/6] drivers: firmware: psci: Implement shallow suspend mode Geert Uytterhoeven 2017-02-20 20:33 ` Geert Uytterhoeven 2017-02-21 10:42 ` Sudeep Holla 2017-02-21 10:42 ` Sudeep Holla 2017-02-21 16:23 ` Geert Uytterhoeven 2017-02-21 16:23 ` Geert Uytterhoeven 2017-02-21 16:23 ` Geert Uytterhoeven 2017-02-21 16:51 ` Sudeep Holla 2017-02-21 16:51 ` Sudeep Holla 2017-02-21 16:51 ` Sudeep Holla 2017-02-21 11:07 ` Pavel Machek 2017-02-21 11:07 ` Pavel Machek 2017-02-21 11:07 ` Pavel Machek 2017-02-21 11:14 ` Sudeep Holla 2017-02-21 11:14 ` Sudeep Holla 2017-02-21 11:14 ` Sudeep Holla 2017-02-21 16:32 ` Geert Uytterhoeven 2017-02-21 16:32 ` Geert Uytterhoeven 2017-02-21 16:32 ` Geert Uytterhoeven 2017-02-21 17:20 ` Mark Rutland 2017-02-21 17:20 ` Mark Rutland 2017-02-21 17:20 ` Mark Rutland 2017-02-21 17:20 ` Mark Rutland 2017-02-21 18:06 ` Geert Uytterhoeven 2017-02-21 18:06 ` Geert Uytterhoeven 2017-02-21 18:06 ` Geert Uytterhoeven 2017-02-21 18:06 ` Geert Uytterhoeven 2017-02-21 18:18 ` Mark Rutland [this message] 2017-02-21 18:18 ` Mark Rutland 2017-02-21 18:18 ` Mark Rutland 2017-02-21 18:23 ` Geert Uytterhoeven 2017-02-21 18:23 ` Geert Uytterhoeven 2017-02-21 18:23 ` Geert Uytterhoeven 2017-02-21 18:23 ` Geert Uytterhoeven 2017-02-21 17:22 ` Sudeep Holla 2017-02-21 17:22 ` Sudeep Holla 2017-02-21 17:22 ` Sudeep Holla 2017-02-21 17:22 ` Sudeep Holla 2017-02-22 13:47 ` Geert Uytterhoeven 2017-02-22 13:47 ` Geert Uytterhoeven 2017-02-22 13:47 ` Geert Uytterhoeven 2017-02-22 14:35 ` Sudeep Holla 2017-02-22 14:35 ` Sudeep Holla 2017-02-22 14:35 ` Sudeep Holla 2017-02-20 20:33 ` [PATCH/RFC 4/6] drivers: firmware: psci: Fix non-PMIC wake-up if SYSTEM_SUSPEND cuts power Geert Uytterhoeven 2017-02-20 20:33 ` Geert Uytterhoeven 2017-02-21 10:50 ` Sudeep Holla 2017-02-21 10:50 ` Sudeep Holla 2017-02-21 16:36 ` Geert Uytterhoeven 2017-02-21 16:36 ` Geert Uytterhoeven 2017-02-21 16:36 ` Geert Uytterhoeven 2017-02-21 16:49 ` Sudeep Holla 2017-02-21 16:49 ` Sudeep Holla 2017-02-21 16:49 ` Sudeep Holla 2017-02-21 11:07 ` Pavel Machek 2017-02-21 11:07 ` Pavel Machek 2017-02-21 16:36 ` Geert Uytterhoeven 2017-02-21 16:36 ` Geert Uytterhoeven 2017-02-21 16:36 ` Geert Uytterhoeven 2017-02-21 17:54 ` Mark Rutland 2017-02-21 17:54 ` Mark Rutland 2017-02-21 17:48 ` Mark Rutland 2017-02-21 17:48 ` Mark Rutland 2017-02-22 14:05 ` Geert Uytterhoeven 2017-02-22 14:05 ` Geert Uytterhoeven 2017-02-22 14:05 ` Geert Uytterhoeven 2017-02-22 14:57 ` Rafael J. Wysocki 2017-02-22 14:57 ` Rafael J. Wysocki 2017-02-22 14:57 ` Rafael J. Wysocki 2017-02-22 14:57 ` Rafael J. Wysocki 2017-02-20 20:33 ` [PATCH/RFC 5/6] arm64: dts: r8a7795: Fix non-PMIC wake-up sources Geert Uytterhoeven 2017-02-20 20:33 ` Geert Uytterhoeven 2017-02-20 20:33 ` Geert Uytterhoeven 2017-02-20 20:33 ` [PATCH/RFC 6/6] arm64: dts: r8a7796: " Geert Uytterhoeven 2017-02-20 20:33 ` Geert Uytterhoeven 2017-02-21 10:38 ` [PATCH/RFC 0/6] PSCI: Fix non-PMIC wake-up if SYSTEM_SUSPEND cuts power Sudeep Holla 2017-02-21 10:38 ` Sudeep Holla 2017-02-21 16:21 ` Geert Uytterhoeven 2017-02-21 16:21 ` Geert Uytterhoeven 2017-02-21 16:21 ` Geert Uytterhoeven 2017-02-21 16:45 ` Sudeep Holla 2017-02-21 16:45 ` Sudeep Holla 2017-02-21 16:45 ` Sudeep Holla 2017-02-21 16:45 ` Sudeep Holla 2017-02-21 17:34 ` Geert Uytterhoeven 2017-02-21 17:34 ` Geert Uytterhoeven 2017-02-21 17:34 ` Geert Uytterhoeven 2017-02-21 17:51 ` Sudeep Holla 2017-02-21 17:51 ` Sudeep Holla 2017-02-21 17:51 ` Sudeep Holla 2017-02-21 18:27 ` Sudeep Holla 2017-02-21 18:27 ` Sudeep Holla 2017-02-21 18:27 ` Sudeep Holla 2017-02-21 18:27 ` Sudeep Holla 2017-02-21 18:45 ` Sudeep Holla 2017-02-21 18:45 ` Sudeep Holla 2017-02-21 18:45 ` Sudeep Holla 2017-02-21 18:45 ` Sudeep Holla 2017-02-22 1:14 ` Rafael J. Wysocki 2017-02-22 1:14 ` Rafael J. Wysocki 2017-02-22 1:14 ` Rafael J. Wysocki 2017-02-22 11:03 ` Sudeep Holla 2017-02-22 11:03 ` Sudeep Holla 2017-02-22 11:03 ` Sudeep Holla 2017-02-22 13:38 ` Geert Uytterhoeven 2017-02-22 13:38 ` Geert Uytterhoeven 2017-02-22 13:38 ` Geert Uytterhoeven 2017-02-22 14:32 ` Sudeep Holla 2017-02-22 14:32 ` Sudeep Holla 2017-02-22 14:32 ` Sudeep Holla 2017-02-22 14:32 ` Sudeep Holla 2017-02-22 14:50 ` Rafael J. Wysocki 2017-02-22 14:50 ` Rafael J. Wysocki 2017-02-22 14:50 ` Rafael J. Wysocki 2017-02-22 14:50 ` Rafael J. Wysocki 2017-02-22 15:24 ` Sudeep Holla 2017-02-22 15:24 ` Sudeep Holla 2017-02-22 15:24 ` Sudeep Holla 2017-02-22 15:24 ` Sudeep Holla 2017-02-23 15:26 ` Geert Uytterhoeven 2017-02-23 15:26 ` Geert Uytterhoeven 2017-02-23 15:26 ` Geert Uytterhoeven 2017-02-23 15:34 ` Geert Uytterhoeven 2017-02-23 15:34 ` Geert Uytterhoeven 2017-02-23 15:34 ` Geert Uytterhoeven 2017-02-23 15:58 ` Sudeep Holla 2017-02-23 15:58 ` Sudeep Holla 2017-02-23 15:58 ` Sudeep Holla 2017-02-23 15:53 ` Sudeep Holla 2017-02-23 15:53 ` Sudeep Holla 2017-02-23 15:53 ` Sudeep Holla 2017-02-23 15:53 ` Sudeep Holla 2017-02-22 13:14 ` Geert Uytterhoeven 2017-02-22 13:14 ` Geert Uytterhoeven 2017-02-22 13:14 ` Geert Uytterhoeven 2017-02-22 14:31 ` Rafael J. Wysocki 2017-02-22 14:31 ` Rafael J. Wysocki 2017-02-22 14:31 ` Rafael J. Wysocki 2017-02-22 14:31 ` Rafael J. Wysocki
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