On Wed, 12 May 2021 16:49:58 +0200
Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx> wrote:
> Em Sun, 9 May 2021 12:33:49 +0100
> Jonathan Cameron <jic23@xxxxxxxxxx> escreveu:
>
> > From: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
> >
> > This case illustrates why the new pm_runtime_sync_and_get() is good
> > in that it makes clear the correct way to handle errors.
> >
> > Calling pm_runtime_put() on failure of the _get() in pm_runtime_get_sync()
> > will potentially result in powering down an already powered down device
> > (as we never successfully powered it up. Unlikely to cause any problems
> > in reality.
> >
> > Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
>
> This one seems a little odd on my eyes, although I don't know much about
> IIO, as it calls RPM get only at:
>
> zpa2326_init_runtime()
>
> on a balanced way, as the routine starts with RPM get() ends with RPM put().
>
> Then it does a put at zpa2326_suspend() and a get at zpa2326_resume().
>
> Can RPM usage_count be zero at suspend (or are there some other part
> of IIO core that increments it?). Because, if after resume, usage_count
> would be equal to 1, as I guess RPM core prevent negative values.
I've stared at this for a few minutes and gotten nowhere in figuring out
the intent. As such I'm going to drop the patch for now and revisit
at a later date.
Jonathan
>
> Regards,
> Mauro
>
>
>
> > ---
> > drivers/iio/pressure/zpa2326.c | 6 ++----
> > 1 file changed, 2 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/iio/pressure/zpa2326.c b/drivers/iio/pressure/zpa2326.c
> > index 89295c90f801..97ac3ba399f7 100644
> > --- a/drivers/iio/pressure/zpa2326.c
> > +++ b/drivers/iio/pressure/zpa2326.c
> > @@ -664,11 +664,9 @@ static int zpa2326_resume(const struct iio_dev *indio_dev)
> > {
> > int err;
> >
> > - err = pm_runtime_get_sync(indio_dev->dev.parent);
> > - if (err < 0) {
> > - pm_runtime_put(indio_dev->dev.parent);
> > + err = pm_runtime_resume_and_get(indio_dev->dev.parent);
> > + if (err < 0)
> > return err;
> > - }
> >
> > if (err > 0) {
> > /*
>
>
>
> Thanks,
> Mauro
