linux-kernel - Re: Re: [PATCH] extcon: arizona: Fix runtime PM imbalance on error

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Date:   Sat, 23 May 2020 10:51:04 +0800 (GMT+08:00)
From:   dinghao.liu@....edu.cn
To:     "Charles Keepax" <ckeepax@...nsource.cirrus.com>
Cc:     kjlu@....edu, "MyungJoo Ham" <myungjoo.ham@...sung.com>,
        "Chanwoo Choi" <cw00.choi@...sung.com>,
        patches@...nsource.cirrus.com, linux-kernel@...r.kernel.org
Subject: Re: Re: [PATCH] extcon: arizona: Fix runtime PM imbalance on error

> On Fri, May 22, 2020 at 07:07:31PM +0800, Dinghao Liu wrote:
> > When arizona_request_irq() returns an error code, a
> > pairing runtime PM usage counter decrement is needed
> > to keep the counter balanced. For error paths after
> > this function, things are the same.
> > 
> > Signed-off-by: Dinghao Liu <dinghao.liu@....edu.cn>
> > ---
> 
> Good spot on the bug thank you.
> 
> >  drivers/extcon/extcon-arizona.c | 1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/drivers/extcon/extcon-arizona.c b/drivers/extcon/extcon-arizona.c
> > index 7401733db08b..470bbc8e5089 100644
> > --- a/drivers/extcon/extcon-arizona.c
> > +++ b/drivers/extcon/extcon-arizona.c
> > @@ -1744,6 +1744,7 @@ static int arizona_extcon_probe(struct platform_device *pdev)
> >  err_rise:
> >  	arizona_free_irq(arizona, jack_irq_rise, info);
> >  err_gpio:
> > +	pm_runtime_put(&pdev->dev);
> 
> However, I don't think this works as a fix. Firstly, the err_gpio
> label is used before the call to pm_runtime_get_sync, this might
> be ok since pm_runtime_enable hasn't been called yet but probably
> better to add a new label for it.
> 

You are right, thank you for your correction! 

> Secondly, following the err_hpdet error path will also result in
> a double put. In that case I don't think there is any reason why
> we need to put before calling input_device_register so it might
> just be simplest to move that put until after registering the
> input device.
> 

Agree. I will fix this in the next edition of patch.

Regards,
Dinghao

> Thanks,
> Charles
> 
> >  	gpiod_put(info->micd_pol_gpio);
> >  err_register:
> >  	pm_runtime_disable(&pdev->dev);
> > -- 
> > 2.17.1
> >