Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Thu, 23 Feb 2017 16:34:50 +0100 | Subject | Re: [PATCH/RFC 0/6] PSCI: Fix non-PMIC wake-up if SYSTEM_SUSPEND cuts power |
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Hi Sudeep,
On Thu, Feb 23, 2017 at 4:26 PM, Geert Uytterhoeven <geert@linux-m68k.org> wrote: > On Wed, Feb 22, 2017 at 3:32 PM, Sudeep Holla <sudeep.holla@arm.com> wrote: >> On 22/02/17 13:38, Geert Uytterhoeven wrote: >>> On Wed, Feb 22, 2017 at 12:03 PM, Sudeep Holla <sudeep.holla@arm.com> wrote: >>> 4. Patch 3/6 adds a new "shallow" state, as it allows to save more >>> power (the difference may be due to suboptimal cpuidle platform support on R-Car Gen3, though), >> >> Why can't you do that in s2idle mode. Please give me the difference >> between your shallow state and s2idle state, not just power numbers >> but the actual state of CPUs and the devices in the system. > > From the Linux side, there's not much difference, except that the secondary > CPU cores are disabled. As that is handled by PSCI, the difference may be > in the PSCI implementation. I will have to check that... > > On these SoCs, the individual CPU cores and the SCU/L2 are in separate > (nested) power areas. Perhaps these power areas are turned off when > disabling the CPU cores, but not when suspending them.
BTW, I don't care much about the extra state.
>>> E.g. on non-PSCI platforms with an Ethernet driver that supports >>> Wake-on-LAN, I can do: >>> >>> ethtool -s eth0 wol g >>> echo mem > /sys/power/state >>> >>> and be sure that the system can be woken up by sending a WoL MagicPacket. >> >> Still possible with s2idle if CPU_SUSPEND is correctly implemented by >> the platform. > > Sure. But not automatic, as it needs fiddling with mem_sleep.
I do care about this, as it affects user experience.
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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