linux-kernel - Re: [PATCH] PM / Domains: add debugfs listing of struct generic_pm

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Date:	Thu, 11 Sep 2014 10:51:11 +0200
From:	Geert Uytterhoeven <geert@...ux-m68k.org>
To:	Maciej Matraszek <m.matraszek@...sung.com>
Cc:	Linux PM list <linux-pm@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Len Brown <len.brown@...el.com>, Pavel Machek <pavel@....cz>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
	Linux-sh list <linux-sh@...r.kernel.org>
Subject: Re: [PATCH] PM / Domains: add debugfs listing of struct generic_pm_domain-s

Hi Maciej,

On Wed, Sep 10, 2014 at 1:28 PM, Maciej Matraszek
<m.matraszek@...sung.com> wrote:
> Add /sys/kernel/debug/pm_genpd/pm_genpd_summary file, which
> lists power domains in the system, their statuses and attached devices,
> resembling /sys/kernel/debug/clk/clk_summary.
>
> Currently it is impossible to inspect (from userland) whether
> a power domain is on or off. And, if it is on, which device blocks it
> from powering down. This change allows developers working on
> embedded devices power efficiency to list all necessary information
> about generic power domains in one place.

Thanks, this is _very_ useful!

> The content of pm_genpd/pm_genpd_summary file is generated by iterating
> over all generic power domain in the system, and, for each,
> over registered devices.

... and over the subdomains, if present.

I can confirm that part is working, too, cfr. the slaves column on r8a7740

    domain                      status         slaves
           /device                                      runtime status
----------------------------------------------------------------------
a4su                            off
a3sg                            off
a3sm                            on
a3sp                            on
    /devices/e6600000.pwm                               suspended
    /devices/e6c50000.serial                            active
    /devices/e6850000.sd                                suspended
    /devices/e6bd0000.mmc                               active
a4s                             on               a3sp, a3sm, a3sg
    /devices/e6900000.irqpin                            unsupported
    /devices/e6900004.irqpin                            unsupported
    /devices/e6900008.irqpin                            unsupported
    /devices/e690000c.irqpin                            unsupported
    /devices/e9a00000.ethernet                          active
a3rv                            off
a4r                             off              a3rv
    /devices/fff20000.i2c                               suspended
a4lc                            off
c5                              on               a4lc, a4r, a4s, a4su
    /devices/e6050000.pfc                               unsupported
    /devices/e6138000.timer                             active

> Signed-off-by: Maciej Matraszek <m.matraszek@...sung.com>

Tested-by: Geert Uytterhoeven <geert+renesas@...der.be>

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-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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