Re: Droid 4: suspend to RAM?

From: Pavel Machek
Date: Wed Aug 08 2018 - 17:32:10 EST


On Wed 2018-08-08 02:05:12, Tony Lindgren wrote:
> * Pavel Machek <pavel@xxxxxx> [180727 11:35]:
> > Hi!
> > > > > high even before modem (and thus USB) is enabled.
> > > > >
> > > > > Interestingly, CyanogenMod and Jolla seem to have higher power
> > > > > consumption than stock operating system.
> > > > >
> > > > > (My Linux can survive for 10 hours, stock system could survive for 4
> > > > > days if I'm not mistaken).
> > > > >
> > > > > I thought I would experiment with suspend to RAM.. and it indeed
> > > > > seemed to suspend ok, but I could not wake it up. Do I need to set up
> > > > > wakeup with button somehow? Is suspend to RAM required for good power
> > > > > consumption?
> > > >
> > > > Sorry but pm subsystem has debug mode that you can test in a easy way.
> > > > You can even wakeup by any rtc alarm easily.
> > >
> > > Yes, that is how it works on PC (but there power button works,
> > > too). Is it expected to work on Droid in v4.18?
> >
> > I tried setting up wakeup using RTC, but no, it does not seem to work:
> >
> > root@devuan:/my/tui/d4# rtcwake -m no -s 5
> > rtcwake: wakeup using /dev/rtc0 at Fri Jul 27 11:28:44 2018
> > root@devuan:/my/tui/d4# echo mem > /sys/power/state
>
> Works for me here as tested on next-20180808, maybe you don't have
> CONFIG_RTC_DRV_CPCAP? Maybe you are trying to use
>CONFIG_RTC_DRV_OMAP?

I tried with mainline... there will be no graphics in next, right? And
yes, I had CONFIG_RTC_DRV_CPCAP and not CONFIG_RTC_DRV_OMAP.

> Then for deeper idle modes, you need to also idle UARTs, and unbind or
> unload USB related modules. You should get to something like 160mW
> power consumption with mdm6600 enabled and SoC suspended that way.

That's slightly interesting. echo mem > /sys/power/state should do all
the work, right? Disable UARTs etc. Plus, is 160mW still a bit high?

> Then again system running idle is about the same with timers and
> interrupts working so I'd just idle UARTs and unload USB modules :)
>
> My UART idle script below for reference.

Thanks, let me try...

Pavel

--
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