linux-kernel - Re: [PATCH v4 23/79] staging: media: ipu3: use pm_runtime_resume_and

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Message-ID: <YI/I+ztnoNUr+u1T@hovoldconsulting.com>
Date:   Mon, 3 May 2021 11:57:15 +0200
From:   Johan Hovold <johan@...nel.org>
To:     Jonathan Cameron <Jonathan.Cameron@...wei.com>
Cc:     Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
        devel@...verdev.osuosl.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linuxarm@...wei.com, linux-kernel@...r.kernel.org,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        mauro.chehab@...wei.com, Bingbu Cao <bingbu.cao@...el.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Tianshu Qiu <tian.shu.qiu@...el.com>,
        linux-media@...r.kernel.org
Subject: Re: [PATCH v4 23/79] staging: media: ipu3: use
 pm_runtime_resume_and_get()

On Fri, Apr 30, 2021 at 06:03:38PM +0100, Jonathan Cameron wrote:
> On Wed, 28 Apr 2021 16:51:44 +0200
> Mauro Carvalho Chehab <mchehab+huawei@...nel.org> wrote:
> 
> > Commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter")
> > added pm_runtime_resume_and_get() in order to automatically handle
> > dev->power.usage_count decrement on errors.
> > 
> > Use the new API, in order to cleanup the error check logic.
> > 
> > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
> Could add that pm_runtime_put() should have been pm_runtime_put_noidle()
> inorder to not potentially result in a call to runtime suspend when
> we never resumed in the first place.

No, that would never happen anyway and any pm_runtime_put() will do
even if pm_runtime_put_noidle() is the natural choice in this case to
balance the counter.

> Otherwise reasonable cleanup.
> 
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
> 
> > ---
> >  drivers/staging/media/ipu3/ipu3.c | 3 +--
> >  1 file changed, 1 insertion(+), 2 deletions(-)
> > 
> > diff --git a/drivers/staging/media/ipu3/ipu3.c b/drivers/staging/media/ipu3/ipu3.c
> > index ee1bba6bdcac..8e1e9e46e604 100644
> > --- a/drivers/staging/media/ipu3/ipu3.c
> > +++ b/drivers/staging/media/ipu3/ipu3.c
> > @@ -392,10 +392,9 @@ int imgu_s_stream(struct imgu_device *imgu, int enable)
> >  	}
> >  
> >  	/* Set Power */
> > -	r = pm_runtime_get_sync(dev);
> > +	r = pm_runtime_resume_and_get(dev);
> >  	if (r < 0) {
> >  		dev_err(dev, "failed to set imgu power\n");
> > -		pm_runtime_put(dev);
> >  		return r;
> >  	}

Johan