All of lore.kernel.org
 help / color / mirror / Atom feed
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
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.

  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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20170221181849.GG8605@leverpostej \
    --to=mark.rutland@arm.com \
    --cc=devicetree@vger.kernel.org \
    --cc=geert+renesas@glider.be \
    --cc=geert@linux-m68k.org \
    --cc=john.stultz@linaro.org \
    --cc=len.brown@intel.com \
    --cc=lina.iyer@linaro.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pm@vger.kernel.org \
    --cc=linux-renesas-soc@vger.kernel.org \
    --cc=lorenzo.pieralisi@arm.com \
    --cc=magnus.damm@gmail.com \
    --cc=pavel@ucw.cz \
    --cc=rjw@rjwysocki.net \
    --cc=robh+dt@kernel.org \
    --cc=sudeep.holla@arm.com \
    --cc=tglx@linutronix.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.