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From: dinghao.liu@zju.edu.cn
To: "Laurent Pinchart" <laurent.pinchart@ideasonboard.com>
Cc: kjlu@umn.edu,
	"Kieran Bingham" <kieran.bingham+renesas@ideasonboard.com>,
	"Mauro Carvalho Chehab" <mchehab@kernel.org>,
	linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: Re: [PATCH] media: vsp1: Fix runtime PM imbalance in vsp1_probe
Date: Mon, 8 Jun 2020 11:03:26 +0800 (GMT+08:00)
Message-ID: <7b79863f.f636d.17291e1ff94.Coremail.dinghao.liu@zju.edu.cn> (raw)
In-Reply-To: <20200608015753.GK22208@pendragon.ideasonboard.com>

Hi Laurent,

> > 
> > I wonder how many bugs we have today, and how many bugs will keep
> > appearing in the future, due to this historical design mistake :-( 
> > 

Good question. It's hard to say if this is a design mistake (some use
of this API does not check its return value and expects it always to
increment the usage counter). But it does make developers misuse it easier.

> > 
> > This change looks good to me, but we also need a similar change in the
> > vsp1_device_get() function if I'm not mistaken. Could you combine both
> > in the same patch ?
> 

Thank you for your advice! I think you are right and I will fix this in the
next version of patch. 

> And actually, after fixing vsp1_device_get(), we should replace the
> pm_runtime_get_sync() call here with vsp1_device_get(), and the
> pm_runtime_put_sync() below with vsp1_device_put(), so there would be no
> need to call pm_runtime_put_sync() manually in the error path here.
> 

The parameter type of vsp1_device_get() and vsp1_device_put() is "struct 
vsp1_device". If we want to use these two wrappers, we need to adjust their 
parameter type to "struct platform_device" or "struct device", which may 
lead to errors in other callers. Maybe we should leave it as it is.

Regards,
Dinghao

  reply index

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-23 11:54 Dinghao Liu
2020-06-08  1:54 ` Laurent Pinchart
2020-06-08  1:57   ` Laurent Pinchart
2020-06-08  3:03     ` dinghao.liu [this message]
2020-06-08  3:11       ` Laurent Pinchart
2020-06-08  3:33         ` dinghao.liu
2020-06-08  7:39       ` Geert Uytterhoeven
2020-06-08 11:54         ` Laurent Pinchart

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