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

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Date:	Thu, 11 Sep 2014 18:45:08 +0200
From:	Maciej Matraszek <m.matraszek@...sung.com>
To:	Geert Uytterhoeven <geert@...ux-m68k.org>
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 Geert!

On Thu, 2014-09-11 at 10:51 +0200, Geert Uytterhoeven wrote:
> 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>

Thanks for testing, Geert, I'm glad you like it :)!
BTW Can I use your output as example in the commit message for v2?
It's much more informative (though 'runtime status' alignment seems
odd).

> 
> 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

-- 
Maciej Matraszek
Samsung R&D Institute Poland
Samsung Electronics


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