linux-kernel - Re: New underflow of regulator enable count warnings in v5.0-rc1

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Date:   Tue, 29 Jan 2019 09:04:44 -0800
From:   Doug Anderson <dianders@...omium.org>
To:     Tony Lindgren <tony@...mide.com>
Cc:     Mark Brown <broonie@...nel.org>,
        Sebastian Reichel <sre@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        linux-omap <linux-omap@...r.kernel.org>
Subject: Re: New underflow of regulator enable count warnings in v5.0-rc1

Hi,

On Tue, Jan 29, 2019 at 8:48 AM Tony Lindgren <tony@...mide.com> wrote:
>
> Hi,
>
> Looks like commit 5451781dadf8 ("regulator: core: Only count load for
> enabled consumers") started showing new warnings with v5.0-rc cycle:
>
> regulator-dummy: Underflow of regulator enable count
>
> I'm seeing this at least with my pwm-vibra test case:
>
> # rumble-test /dev/input/by-path/platform-vibrator-event 0xffff
> pwm-vibrator vibrator: vibrator supply vcc not found, using dummy regulator
> input: pwm-vibrator as /devices/platform/vibrator/input/input4
> regulator-dummy: Underflow of regulator enable count
> Upload rumble effect... id=0
> regulator-dummy: Underflow of regulator enable count
>
> Are these bogus warnings for dummy regulator or do we have
> real unpaired regulator calls or somewhere?

My first guess is that there's a real unpaired regulator call somewhere.

I actually meant to include this in the commit message, but I'm an
idiot and I used "--" to break up the parts of the commit message
which confused git when Mark applied it.  Sigh.  For the full commit
message, see:

https://lkml.kernel.org/r/20181120175255.227783-1-dianders@chromium.org

In that message I said:

> - We can (and will) spit errors out for code that used to be invalid
>   but was never caught before.  Specifically if someone leaves a
>   regulator enabled and calls regulator_put() we'll yell.  We'll also
>   yell if a single consumer calls more disables than enables.

Looking quickly at 'pwm-vibra.c' it wouldn't surprise me at all if you
call regulator_disable() more times than regulator_enable().  If
that's true it should be fixed.

-Doug