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Date: Mon, 27 May 2024 07:31:27 +0000
From: Sakari Ailus <sakari.ailus@iki.fi>
To: Benjamin Mugnier <benjamin.mugnier@foss.st.com>
Cc: Sylvain Petinot <sylvain.petinot@foss.st.com>, mchehab@kernel.org,
	robh@kernel.org, krzysztof.kozlowski+dt@linaro.org,
	conor+dt@kernel.org, linux-media@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	hdegoede@redhat.com, laurent.pinchart@ideasonboard.com
Subject: Re: [PATCH 2/2] media: i2c: Add driver for ST VD56G3 camera sensor
Message-ID: <ZlQ2zymJguCipLMl@valkosipuli.retiisi.eu>
References: <20240417133453.17406-1-sylvain.petinot@foss.st.com>
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 <Zil1wiCcCdwZs5Df@valkosipuli.retiisi.eu>
 <d45a2ea1-bc2d-441a-b036-1da40290c6b3@foss.st.com>
 <c9b35dc4-6f52-48e2-8952-5a43c500f819@foss.st.com>
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In-Reply-To: <c9b35dc4-6f52-48e2-8952-5a43c500f819@foss.st.com>

Hi Benjamin,

On Mon, May 13, 2024 at 03:37:25PM +0200, Benjamin Mugnier wrote:
> >>> +static int vd56g3_read_expo_cluster(struct vd56g3 *sensor, bool force_cur_val)
> >>> +{
> >>> +	u64 exposure = 0;
> >>> +	u64 again = 0;
> >>> +	u64 dgain = 0;
> >>
> >> Do you need the assignments? The values are assigned by cci_read() below,
> >> right?
> > 
> > Well initially, I didn't have those assignments and some checker
> > complains (Honestly I didn't investigate the warning).
> > I will double check and see if they are necessary.
> > 
> 
> Since I have smatch ready, I ran it without these initialization against
> the latest media tree. I got these :
> 
> drivers/media/i2c/st-vd56g3.c:403 vd56g3_read_expo_cluster() error:
> uninitialized symbol 'exposure'.
> drivers/media/i2c/st-vd56g3.c:404 vd56g3_read_expo_cluster() error:
> uninitialized symbol 'again'.
> drivers/media/i2c/st-vd56g3.c:405 vd56g3_read_expo_cluster() error:
> uninitialized symbol 'dgain'.
> drivers/media/i2c/st-vd56g3.c:407 vd56g3_read_expo_cluster() error:
> uninitialized symbol 'exposure'.
> drivers/media/i2c/st-vd56g3.c:408 vd56g3_read_expo_cluster() error:
> uninitialized symbol 'again'.
> drivers/media/i2c/st-vd56g3.c:409 vd56g3_read_expo_cluster() error:
> uninitialized symbol 'dgain'.
> 
> cci_read() is indeed not modifying its 'var' argument in the default
> case of the switch [1]. Spawning these errors.
> Adding a '*val = 0' in the default case would also fix it, but will
> change the function behavior.

I think I'd add the assignment to cci_read(). This isn't the only driver
that's affected. In the best case smatch would be fixed to figure this out.

Any thoughts?

Cc also Hans and Laurent.

-- 
Regards,

Sakari Ailus