Re: [PATCH 07/13] ARM: dts: r8a7792: initial SoC device tree

From: Simon Horman <horms@verge.net.au>
To: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
	linux-renesas-soc@vger.kernel.org,
	Rob Herring <robh+dt@kernel.org>, Pawel Moll <pawel.moll@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Ian Campbell <ijc+devicetree@hellion.org.uk>,
	Kumar Gala <galak@codeaurora.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	Magnus Damm <magnus.damm@gmail.com>,
	Russell King <linux@arm.linux.org.uk>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 07/13] ARM: dts: r8a7792: initial SoC device tree
Date: Thu, 16 Jun 2016 09:06:49 +0900	[thread overview]
Message-ID: <20160616000649.GA2709@verge.net.au> (raw)
In-Reply-To: <efac403f-3709-6a1a-aa02-a8ab26b21ffc@cogentembedded.com>

On Wed, Jun 15, 2016 at 12:08:21AM +0300, Sergei Shtylyov wrote:
> Hello.
> 
> On 06/14/2016 03:43 AM, Simon Horman wrote:
> 
> >>>>[...]
> >>>>
> >>>>>>>And that the system behaves sanely on suspend/resume.
> >>>>>>
> >>>>>> I'd be thankful if you told me how to test that. :-)
> >>>>>
> >>>>>System suspend:
> >>>>>
> >>>>>  echo mem > /sys/power/state
> >>>>
> >>>>  Oh. I know that one! :-)
> >>>>
> >>>>>System resume: You're gonna need a "wakeup-source" in your DTS, e.g. gpio-keys.
> >>>>>Serial should work too, echo "enabled" to the corresponding wakeup
> >>>>>file in /sys first.
> >>>>
> >>>>  I'm afraid I couldn't find that file. All I saw were RPM controls...
> >>>>
> >>>>>In case of issues, try "echo 0 > /sys/module/printk/parameters/console_suspend".
> >>>>
> >>>>  There's no problems suspending, it's the resuming that's a problem for me.
> >>>>
> >>>>>Good luck!
> >>>>
> >>>>  As usual, there was no luck. :-)
> >>>>
> >>>>WBR, Sergei
> >>>
> >>>Does resume work for UP (i.e. without SMP)?
> >>
> >>   No. My problem with resume is I can't wake up the remote system. I don't
> >>see the needed 'wakeup' file in
> >>/sys/devices/platform/soc/e6e60000.serial/...
> >>    However, if I enable CONFIG_PM_[ADVANCED_]DEBUG and do
> >>
> >>$ echo -n core /sys/.power/pm_test
> >>
> >>the system happily wakes up after a small delay (5 s), w/either SMP or UP kernel.
> >
> >That seems promising but it seems curious that there is no wakeup file.
> >
> >On Lager the following procedure works for me using
> >renesas-devel-20160613-v4.7-rc3 and shmobile defconfig.
> >
> >0. Add wakeup-source property to serial@e6ce0000 node in DT
> 
>    Ah, stupid me, it was the piece that I'd overlooked!
> 
> >1. echo enabled > /sys/devices/platform/e6e60000.serial/tty/ttySC0/power/wakeup
> >2. echo mem > /sys/power/state
> >3. Provide input on serial console
> >
> >* Success! *
> 
>    Yeah, works now!
>    Sorry, I had no previous experience with the PM. Was unsupported feature
> back in MontaVista... :-)

Great, thanks for your persistence.

FWIW, I always have to refer to some notes in order to exercise PM.

> >>>How did testing CPU hotplug go? Did it work for all CPUs?
> >>
> >>   Sure!
> >
> >Great!
> >
> >>   The only problem I'm seeing (again) is the RCAN clock failing to register:
> >>
> >>rcar_gen2_cpg_clocks_init: failed to register cpg_clocks rcan clock (-12)
> >>
> >>   I was going to look at it yesterday but (wrongly) thought it somehow
> >>cured itself... I'll look at it now.
> >
> >Is this resolved? If not perhaps you could consider removing the node
> >in question for now.
> 
>    That's what I did in v5, i.e. removed the RCAN CPG clock (not the whole
> node)...

Great.