From: geert@linux-m68k.org (Geert Uytterhoeven)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH/RFC 0/6] PSCI: Fix non-PMIC wake-up if SYSTEM_SUSPEND cuts power
Date: Tue, 21 Feb 2017 17:21:06 +0100 [thread overview]
Message-ID: <CAMuHMdWjseO3XSOH2XCbM411Aj12RpdZZbHkpfFUfej58myz5Q@mail.gmail.com> (raw)
In-Reply-To: <69ab75a1-2e04-19e2-d1ad-12ca1cfc7625@arm.com>
Hi Sudeep,
On Tue, Feb 21, 2017 at 11:38 AM, Sudeep Holla <sudeep.holla@arm.com> wrote:
> On 20/02/17 20:33, Geert Uytterhoeven wrote:
>> This patch series adds support for using non-PMIC wake-up sources on the
>> Renesas R-Car Gen3 (H3 or M3-W) Salvator-X development boards.
>>
>> Nothing in the PSCI specification requires the SoC to remain powered and
>> to support wake-up sources when suspended using SYSTEM_SUSPEND.
>> If the firmware implements the PSCI SYSTEM_SUSPEND operation by cutting
>> power to the SoC, the only possibly wake-up sources are thus the ones
>> connected to the PMIC.
>
> OK, but I don't see any issue with that. That's exactly how it works on
How do you use other wake-up sources, like wake on LAN, UART or GPIO?
> ARM Juno platform. The SoC is powered down.
Good to hear this is not limited to Renesas platforms, so there's a common
problem to solve.
>> To allow other wake-up sources, this patch series documents and adds
>> support for an "arm,psci-system-suspend-is-power-down" DT property, so
>
> NACK, you don't need any such properties.
If this is true for all PSCI platforms, there's indeed no need for such a
property, and drivers/firmware/psci.c should default to this case.
>> Linux uses a different suspend method when other wake-up sources (e.g.
>> wake on LAN, UART or GPIO) are enabled. Hence the user no longer has to
>> manually restrict "mem" suspend to "s2idle" or "shallow" states using:
>
> Have you explored suspend-to-idle instead ? It looks like thats exactly
> what you are doing in this patch set. You also get low latency for free
> as it just enters the deepest idle state on all CPUs instead of
> hotplugging out all the secondaries.
Yes, cfr. "s2idle" above.
The user can specify to use "s2idle" manually:
$ echo s2idle > /sys/power/mem_sleep # or "shallow"
However, how to handle this automatically, e.g. by a distro?
On most other platforms, userspace can just do e.g.
ethtool -s eth0 wol g
to enable wake-on-LAN, and suspend to the deepest supported state using:
echo mem > /sys/power/state
On systems where PSCI SYSTEM_SUSPEND powers down the SoC, userspace must
make sure to configure to use "s2idle" (or "shallow) instead, else the
configured wake-up sources won't work.
I want Linux to handle this automatically.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
next prev parent reply other threads:[~2017-02-21 16:21 UTC|newest]
Thread overview: 48+ 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 ` [PATCH/RFC 1/6] alarmtimer: Postpone wake-up source registration until really available Geert Uytterhoeven
2017-02-20 20:33 ` [PATCH/RFC 2/6] PM / Wakeup: Add wakeup_source_available() Geert Uytterhoeven
2017-02-20 20:33 ` [PATCH/RFC 3/6] drivers: firmware: psci: Implement shallow suspend mode Geert Uytterhoeven
2017-02-21 10:42 ` Sudeep Holla
2017-02-21 16:23 ` Geert Uytterhoeven
2017-02-21 16:51 ` Sudeep Holla
2017-02-21 11:07 ` Pavel Machek
2017-02-21 11:14 ` Sudeep Holla
2017-02-21 16:32 ` Geert Uytterhoeven
2017-02-21 17:20 ` Mark Rutland
2017-02-21 18:06 ` Geert Uytterhoeven
2017-02-21 18:18 ` Mark Rutland
2017-02-21 18:23 ` Geert Uytterhoeven
2017-02-21 17:22 ` Sudeep Holla
2017-02-22 13:47 ` Geert Uytterhoeven
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
2017-02-21 10:50 ` Sudeep Holla
2017-02-21 16:36 ` Geert Uytterhoeven
2017-02-21 16:49 ` Sudeep Holla
2017-02-21 11:07 ` Pavel Machek
2017-02-21 16:36 ` Geert Uytterhoeven
2017-02-21 17:54 ` Mark Rutland
2017-02-21 17:48 ` Mark Rutland
2017-02-22 14:05 ` Geert Uytterhoeven
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 ` [PATCH/RFC 6/6] arm64: dts: r8a7796: " 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 16:21 ` Geert Uytterhoeven [this message]
2017-02-21 16:45 ` Sudeep Holla
2017-02-21 17:34 ` Geert Uytterhoeven
2017-02-21 17:51 ` Sudeep Holla
2017-02-21 18:27 ` Sudeep Holla
2017-02-21 18:45 ` Sudeep Holla
2017-02-22 1:14 ` Rafael J. Wysocki
2017-02-22 11:03 ` Sudeep Holla
2017-02-22 13:38 ` Geert Uytterhoeven
2017-02-22 14:32 ` Sudeep Holla
2017-02-22 14:50 ` Rafael J. Wysocki
2017-02-22 15:24 ` Sudeep Holla
2017-02-23 15:26 ` Geert Uytterhoeven
2017-02-23 15:34 ` Geert Uytterhoeven
2017-02-23 15:58 ` Sudeep Holla
2017-02-23 15:53 ` Sudeep Holla
2017-02-22 13:14 ` Geert Uytterhoeven
2017-02-22 14:31 ` Rafael J. Wysocki
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