Re: [PATCH 0/2] PM / core: genpd fix and pm_runtime_force_suspend|resume() rework

From: Geert Uytterhoeven <geert@linux-m68k.org>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Linux PM <linux-pm@vger.kernel.org>,
	Ulf Hansson <ulf.hansson@linaro.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>
Subject: Re: [PATCH 0/2] PM / core: genpd fix and pm_runtime_force_suspend|resume() rework
Date: Fri, 12 Jan 2018 15:31:09 +0100	[thread overview]
Message-ID: <CAMuHMdX6dJzOcxkWyDR6anpcwZU5fy03sTeChEp35KY0d40iFg@mail.gmail.com> (raw)
In-Reply-To: <4928977.5hd79RbQlp@aspire.rjw.lan>

Hi Rafael,

On Fri, Jan 12, 2018 at 2:00 PM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> This comes from the recent discussion/testing effort that ensued after my
> pm_runtime_force_suspend|resume() changes proposal:
>
> https://marc.info/?t=151497772000004&r=1&w=2
>
> Patch [1/2] basically is https://patchwork.kernel.org/patch/10152873/ rebased
> on top of the current linux-next branch of the linux-pm.git tree (the relevant
> part should be there in the linux-next tree proper ATM).  It applies on top
> of https://patchwork.kernel.org/patch/10156077/ which should apply to the Linus'
> tree cleanly.
>
> Patch [2/2] is a resend of https://patchwork.kernel.org/patch/10142047/ with
> a very minor changelog modification and the R-b tag from Ulf.
>
> Geert, if possible, please test this on the Renesas systems that had the
> problem with https://patchwork.kernel.org/patch/10142047/ previously and let
> me know if you still see issues.

I've tested this on two very similar systems: Salvator-XS with R-Car H3 ES2.0,
and Salvator-X with R-Car M3-W ES1.0.

On the M3-based system, everything seems to work fine.
On the H3-based system, the serial console (the /dev/ttySC0 device, not kernel
serial output) is dead after resume from s2ram, with and without
no_console_suspend.

With no_console_suspend, I see:

    ttySC ttySC0: 1 input overrun(s)

after typing on the serial console, so it looks like an interrupt problem.

This issue seems to be caused by patch [1/2]. But I have no idea what's
really happening, and why the two systems behave differently.

Oh well, have a nice weekend!

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