linux-kernel - Re: [PATCH v3 8/9] media: i2c: ov5645: Don't return early on failures for s

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Date:   Wed, 26 Oct 2022 19:17:21 +0200
From:   Marco Felsch <m.felsch@...gutronix.de>
To:     Prabhakar <prabhakar.csengg@...il.com>
Cc:     Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        NXP Linux Team <linux-imx@....com>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Magnus Damm <magnus.damm@...il.com>,
        Hans Verkuil <hverkuil@...all.nl>,
        Shawn Tu <shawnx.tu@...el.com>, devicetree@...r.kernel.org,
        Jacopo Mondi <jacopo@...ndi.org>, linux-kernel@...r.kernel.org,
        Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>,
        linux-renesas-soc@...r.kernel.org,
        Biju Das <biju.das.jz@...renesas.com>,
        linux-arm-kernel@...ts.infradead.org, linux-media@...r.kernel.org
Subject: Re: [PATCH v3 8/9] media: i2c: ov5645: Don't return early on
 failures for s_stream(0)

Hi Prabhakar,

thanks for the patch, please see below my comments.

On 22-10-26, Prabhakar wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> 
> Make sure we dont stop the code flow in case of errors while stopping
> the stream and return the error code of the first error case if any.
> 
> v4l2-core takes care of warning the user so no need to add a warning
> message in the driver.
> 
> Suggested-by: Sakari Ailus <sakari.ailus@...ux.intel.com>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> ---
> v2->v3
> * Now propagating the first error code in case of failure.
> 
> v1->v2
> * New patch
> ---
>  drivers/media/i2c/ov5645.c | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/media/i2c/ov5645.c b/drivers/media/i2c/ov5645.c
> index eea3067ddc8b..5702a55607fc 100644
> --- a/drivers/media/i2c/ov5645.c
> +++ b/drivers/media/i2c/ov5645.c
> @@ -996,17 +996,22 @@ static int ov5645_s_stream(struct v4l2_subdev *subdev, int enable)
>  		if (ret < 0)
>  			goto err_rpm_put;
>  	} else {
> +		int stream_off_ret = 0;
> +
>  		ret = ov5645_write_reg(ov5645, OV5645_IO_MIPI_CTRL00, 0x40);

If this write failed..

>  		if (ret < 0)
> -			return ret;
> +			stream_off_ret = ret;
>  
>  		ret = ov5645_write_reg(ov5645, OV5645_SYSTEM_CTRL0,
>  				       OV5645_SYSTEM_CTRL0_STOP);

why should this write be successful?

Regards,
  Marco

> -		if (ret < 0)
> -			return ret;
> +		if (ret < 0 && !stream_off_ret)
> +			stream_off_ret = ret;
>  
>  		pm_runtime_mark_last_busy(ov5645->dev);
>  		pm_runtime_put_autosuspend(ov5645->dev);
> +
> +		if (stream_off_ret)
> +			return stream_off_ret;
>  	}
>  
>  	return 0;
> -- 
> 2.25.1
> 
> 
>