[PATCH/RFC 3/6] drivers: firmware: psci: Implement shallow suspend mode

Sudeep Holla
2017-02-21T16:51:48Z

On 21/02/17 16:23, Geert Uytterhoeven wrote:
> Hi Sudeep,
>
> On Tue, Feb 21, 2017 at 11:42 AM, Sudeep Holla <sudeep.holla@arm.com> wrote:
>> On 20/02/17 20:33, Geert Uytterhoeven wrote:
>>> 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.
>>>
>>> List the available system suspend modes:
>>>
>>> $ cat /sys/power/mem_sleep
>>> s2idle shallow [deep]
>>>
>>> Suspend to "shallow" mode:
>>>
>>> $ echo shallow > /sys/power/mem_sleep
>>> $ echo mem > /sys/power/state
>>>
>>
>> I don't have the links to such previous attempts handy, but we have
>
> Don't worry, I did read earlier discussions about implementing shallow mode.
>

In short or just to summarize in one line, just use "freeze"(a.k.a
suspend-to-idle suspend mode)

--
Regards,
Sudeep