Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Tue, 21 Feb 2017 17:23:48 +0100 | Subject | Re: [PATCH/RFC 3/6] drivers: firmware: psci: Implement shallow suspend mode |
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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.
> more elegant alternative options(suspend-to-idle) and any such attempts > to hack around the PSCI will be NACKed.
"s2idle" does not power down secondary CPU cores, so this is an improvement. "deep" may not support configured wake-up sources, which is a bug.
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@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
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