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From: Sudeep Holla <sudeep.holla@arm.com>
To: Pavel Machek <pavel@ucw.cz>,
	Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Sudeep Holla <sudeep.holla@arm.com>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Mark Rutland <mark.rutland@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, linux-arm-kernel@lists.infradead.org,
	linux-renesas-soc@vger.kernel.org, linux-pm@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 11:14:16 +0000	[thread overview]
Message-ID: <de2a15d4-9ac2-9ba9-a47a-eacbf478f601@arm.com> (raw)
In-Reply-To: <20170221110712.GB5021@amd>



On 21/02/17 11:07, Pavel Machek wrote:
> Hi!
> 
>> Enable support for "shallow" suspend mode, also known as "Standby" or
>> "Power-On Suspend".
>>
>> As secondary CPU cores are taken offline, "shallow" suspend mode saves
>> slightly more power than "s2idle", but less than "deep" suspend mode.
>> However, unlike "deep" suspend mode, "shallow" suspend mode can be used
>> regardless of the presence of support for PSCI_SYSTEM_SUSPEND, which is
>> an optional API in PSCI v1.0.
> 
> If system supports "shallow" suspend, why does not PSCI implement it?
> 

Yes it can, and IIUC it already does on this platform with CPU_SUSPEND.
All it now needs is just to use existing "freeze" suspend mode in Linux.

> In the past, I was told PSCI will not turn into ACPI-like mess, and
> that we'll be able to fix PSCI and will not have to work around its
> problems in kernel :-(.

Can you be more elaborate on the mess you see on this Renesas platform.

For me, it looks like this patch is attempting to *re-implement* the
existing "suspend-to-idle" functionality. So IMO, this patch set is
creating unnecessary mess giving an illusion that PSCI specification is
broken.

-- 
Regards,
Sudeep

WARNING: multiple messages have this Message-ID
From: Sudeep Holla <sudeep.holla-5wv7dgnIgG8@public.gmane.org>
To: Pavel Machek <pavel-+ZI9xUNit7I@public.gmane.org>,
	Geert Uytterhoeven
	<geert+renesas-gXvu3+zWzMSzQB+pC5nmwQ@public.gmane.org>
Cc: Sudeep Holla <sudeep.holla-5wv7dgnIgG8@public.gmane.org>,
	Lorenzo Pieralisi
	<lorenzo.pieralisi-5wv7dgnIgG8@public.gmane.org>,
	Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>,
	Lina Iyer <lina.iyer-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	John Stultz <john.stultz-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>,
	"Rafael J . Wysocki"
	<rjw-LthD3rsA81gm4RdzfppkhA@public.gmane.org>,
	Len Brown <len.brown-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
	Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Magnus Damm <magnus.damm-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	linux-renesas-soc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-pm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH/RFC 3/6] drivers: firmware: psci: Implement shallow suspend mode
Date: Tue, 21 Feb 2017 11:14:16 +0000	[thread overview]
Message-ID: <de2a15d4-9ac2-9ba9-a47a-eacbf478f601@arm.com> (raw)
In-Reply-To: <20170221110712.GB5021@amd>



On 21/02/17 11:07, Pavel Machek wrote:
> Hi!
> 
>> Enable support for "shallow" suspend mode, also known as "Standby" or
>> "Power-On Suspend".
>>
>> As secondary CPU cores are taken offline, "shallow" suspend mode saves
>> slightly more power than "s2idle", but less than "deep" suspend mode.
>> However, unlike "deep" suspend mode, "shallow" suspend mode can be used
>> regardless of the presence of support for PSCI_SYSTEM_SUSPEND, which is
>> an optional API in PSCI v1.0.
> 
> If system supports "shallow" suspend, why does not PSCI implement it?
> 

Yes it can, and IIUC it already does on this platform with CPU_SUSPEND.
All it now needs is just to use existing "freeze" suspend mode in Linux.

> In the past, I was told PSCI will not turn into ACPI-like mess, and
> that we'll be able to fix PSCI and will not have to work around its
> problems in kernel :-(.

Can you be more elaborate on the mess you see on this Renesas platform.

For me, it looks like this patch is attempting to *re-implement* the
existing "suspend-to-idle" functionality. So IMO, this patch set is
creating unnecessary mess giving an illusion that PSCI specification is
broken.

-- 
Regards,
Sudeep
--
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WARNING: multiple messages have this Message-ID
From: sudeep.holla@arm.com (Sudeep Holla)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH/RFC 3/6] drivers: firmware: psci: Implement shallow suspend mode
Date: Tue, 21 Feb 2017 11:14:16 +0000	[thread overview]
Message-ID: <de2a15d4-9ac2-9ba9-a47a-eacbf478f601@arm.com> (raw)
In-Reply-To: <20170221110712.GB5021@amd>



On 21/02/17 11:07, Pavel Machek wrote:
> Hi!
> 
>> Enable support for "shallow" suspend mode, also known as "Standby" or
>> "Power-On Suspend".
>>
>> As secondary CPU cores are taken offline, "shallow" suspend mode saves
>> slightly more power than "s2idle", but less than "deep" suspend mode.
>> However, unlike "deep" suspend mode, "shallow" suspend mode can be used
>> regardless of the presence of support for PSCI_SYSTEM_SUSPEND, which is
>> an optional API in PSCI v1.0.
> 
> If system supports "shallow" suspend, why does not PSCI implement it?
> 

Yes it can, and IIUC it already does on this platform with CPU_SUSPEND.
All it now needs is just to use existing "freeze" suspend mode in Linux.

> In the past, I was told PSCI will not turn into ACPI-like mess, and
> that we'll be able to fix PSCI and will not have to work around its
> problems in kernel :-(.

Can you be more elaborate on the mess you see on this Renesas platform.

For me, it looks like this patch is attempting to *re-implement* the
existing "suspend-to-idle" functionality. So IMO, this patch set is
creating unnecessary mess giving an illusion that PSCI specification is
broken.

-- 
Regards,
Sudeep

  reply	other threads:[~2017-02-21 11:14 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 [this message]
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
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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