Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH 58/78] media: exynos-gsc: use
 pm_runtime_resume_and_get()
To:     Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Cc:     linuxarm@huawei.com, mauro.chehab@huawei.com,
        Ezequiel Garcia <ezequiel@collabora.com>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-media@vger.kernel.org, linux-samsung-soc@vger.kernel.org
From:   Sylwester Nawrocki <s.nawrocki@samsung.com>
Message-ID: <ee7b580a-d5bc-bdbf-3efc-c9d8f43316db@samsung.com>
Date:   Tue, 27 Apr 2021 10:18:12 +0200
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0)
        Gecko/20100101 Thunderbird/78.10.0
MIME-Version: 1.0
In-Reply-To: <9c7d683907b9f9cf4a99f57f978671ec7f5a1dbc.1619191723.git.mchehab+huawei@kernel.org>
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Content-Type: text/plain; charset="utf-8"
CMS-TYPE: 201P
References: <cover.1619191723.git.mchehab+huawei@kernel.org>
        <CGME20210424064556eucas1p1e89378837c377168c9782b4172e70482@eucas1p1.samsung.com>
        <9c7d683907b9f9cf4a99f57f978671ec7f5a1dbc.1619191723.git.mchehab+huawei@kernel.org>
Precedence: bulk

On 24.04.2021 08:45, Mauro Carvalho Chehab 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@kernel.org>
> ---
>  drivers/media/platform/exynos-gsc/gsc-core.c | 3 +--
>  drivers/media/platform/exynos-gsc/gsc-m2m.c  | 2 +-
>  2 files changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/media/platform/exynos-gsc/gsc-core.c b/drivers/media/platform/exynos-gsc/gsc-core.c
> index 9f41c2e7097a..9d5841194f6b 100644
> --- a/drivers/media/platform/exynos-gsc/gsc-core.c
> +++ b/drivers/media/platform/exynos-gsc/gsc-core.c
> @@ -1210,7 +1210,7 @@ static int gsc_remove(struct platform_device *pdev)
>  	struct gsc_dev *gsc = platform_get_drvdata(pdev);
>  	int i;
>  
> -	pm_runtime_get_sync(&pdev->dev);
> +	pm_runtime_resume_and_get(&pdev->dev);
>  
>  	gsc_unregister_m2m_device(gsc);
>  	v4l2_device_unregister(&gsc->v4l2_dev);
> @@ -1219,7 +1219,6 @@ static int gsc_remove(struct platform_device *pdev)
>  	for (i = 0; i < gsc->num_clocks; i++)
>  		clk_disable_unprepare(gsc->clock[i]);
>  
> -	pm_runtime_put_noidle(&pdev->dev);

If we do this then the device usage count will not get decremented
after the pm_runtime_resume_and_get() call above and after driver
unload/load cycle it will not be possible to suspend the device.
I wouldn't be changing anything in gsc_remove(), pm_runtime_get_sync()
works better in that case.

Regards,
Sylwester

>  	pm_runtime_disable(&pdev->dev);
>  
>  	dev_dbg(&pdev->dev, "%s driver unloaded\n", pdev->name