Re: Re: [PATCH] iio: magnetometer: ak8974: Fix runtime PM imbalance on error

[Linus Walleij]

On Tue, May 26, 2020 at 7:14 AM <dinghao.liu@xxxxxxxxxx> wrote:
> > On Sun, May 24, 2020 at 4:51 AM Dinghao Liu <dinghao.liu@xxxxxxxxxx> wrote:

> > >  disable_pm:
> > > -       pm_runtime_put_noidle(&i2c->dev);
> > >         pm_runtime_disable(&i2c->dev);
> > >         ak8974_set_power(ak8974, AK8974_PWR_OFF);
> >
> > Keep the top pm_runtime_put_noidle().
>
> I found that there was already a pm_runtime_put() before
> iio_triggered_buffer_setup() (just after pm_runtime_use_autosuspend).
> So if we keep the pm_runtime_put_noidle() here, we will have
> two pmusage counter decrement. Do you think this is a bug?

Yes you're right.

What about just moving the pm_runtime_put() until the end
of the initialization? Right before return 0;
Then we can keep this nice goto exits as they are.

Maybe move all these three:

      pm_runtime_set_autosuspend_delay(&i2c->dev,
                                         AK8974_AUTOSUSPEND_DELAY);
        pm_runtime_use_autosuspend(&i2c->dev);
        pm_runtime_put(&i2c->dev);

Yours,
Linus Walleij