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From: Stephen Boyd <sboyd@kernel.org>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>,
	Michael Turquette <mturquette@baylibre.com>,
	"Rafael J . Wysocki" <rjw@rjwysocki.net>,
	Kevin Hilman <khilman@kernel.org>,
	Ulf Hansson <ulf.hansson@linaro.org>,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
	linux-clk <linux-clk@vger.kernel.org>,
	Linux PM list <linux-pm@vger.kernel.org>
Subject: Re: [PATCH 1/3] clk: renesas: mstp: Set GENPD_FLAG_ALWAYS_ON for clock domain
Date: Fri, 16 Aug 2019 20:48:11 -0700	[thread overview]
Message-ID: <20190817034812.5435B21721@mail.kernel.org> (raw)
In-Reply-To: <CAMuHMdVvwsXU2YwFRA2Y2K9KKzF4L-hqDudarmc-OeHXRMCifQ@mail.gmail.com>

Quoting Geert Uytterhoeven (2019-08-16 12:59:32)
> Hi Stephen,
> 
> On Fri, Aug 16, 2019 at 8:01 PM Stephen Boyd <sboyd@kernel.org> wrote:
> > Quoting Geert Uytterhoeven (2019-08-16 05:52:23)
> > > The CPG/MSTP Clock Domain driver does not implement the
> > > generic_pm_domain.power_{on,off}() callbacks, as the domain itself
> > > cannot be powered down.  Hence the domain should be marked as always-on
> > > by setting the GENPD_FLAG_ALWAYS_ON flag.
> > >
> > > This gets rid of the following boot warning on RZ/A1:
> > >
> > >     sh_mtu2 fcff0000.timer: PM domain cpg_clocks will not be powered off
> > >
> > > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> > > ---
> >
> > Are you going to add a Fixes tag?
> 
> I didn't add a Fixes tag, as there's no clear point in history where the
> problem appeared: the Clock Domain code in this driver predates the
> introduction of the GENPD_FLAG_ALWAYS_ON flag by ca. 18 months.
> 
> Candidates are:
> d716f4798ff8c65a ("PM / Domains: Support IRQ safe PM domains")
> ffaa42e8a40b7f10 ("PM / Domains: Enable users of genpd to specify
> always on PM domains")
> 075c37d59ecd4a8b ("PM / Domains: Don't warn about IRQ safe device for
> an always on PM domain")
> 
> Do you think it's worth adding one or more of the above?
> Thanks!
> 

Well is it actually a problem to not specify the flag? I guess it's just
a potential problem if the genpd is ever powered off, but given that the
governor decides to leave it always enabled it doesn't actually matter?
So it's not really fixing anything besides silencing a harmless warning?


  reply	other threads:[~2019-08-17  3:48 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-16 12:52 [PATCH 0/3] clk: renesas: Set GENPD_FLAG_ALWAYS_ON for clock domain Geert Uytterhoeven
2019-08-16 12:52 ` [PATCH 1/3] clk: renesas: mstp: " Geert Uytterhoeven
2019-08-16 15:38   ` Simon Horman
2019-08-16 18:01   ` Stephen Boyd
2019-08-16 19:59     ` Geert Uytterhoeven
2019-08-17  3:48       ` Stephen Boyd [this message]
2019-08-18  8:27         ` Geert Uytterhoeven
2019-08-22 14:06           ` Ulf Hansson
2019-08-23  8:59             ` Geert Uytterhoeven
2019-08-16 12:52 ` [PATCH 2/3] clk: renesas: r9a06g032: " Geert Uytterhoeven
2019-08-16 15:39   ` Simon Horman
2019-08-16 12:52 ` [PATCH 3/3] clk: renesas: cpg-mssr: " Geert Uytterhoeven
2019-08-16 15:39   ` Simon Horman
2019-08-22 14:08 ` [PATCH 0/3] clk: renesas: " Ulf Hansson
2019-08-23  9:08   ` Geert Uytterhoeven

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