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Message-ID: <4f666fe5-080e-6c82-5bef-c0b52cb57207@foss.st.com>
Date:   Tue, 8 Feb 2022 09:52:32 +0100
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Subject: Re: [PATCH] drm/stm: Avoid using val uninitialized in
 ltdc_set_ycbcr_config()
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To:     Nathan Chancellor <nathan@kernel.org>,
        Yannick Fertre <yannick.fertre@foss.st.com>,
        Philippe Cornu <philippe.cornu@foss.st.com>,
        Benjamin Gaignard <benjamin.gaignard@linaro.org>
CC:     <llvm@lists.linux.dev>, Nick Desaulniers <ndesaulniers@google.com>,
        <linux-kernel@vger.kernel.org>, <dri-devel@lists.freedesktop.org>,
        <linux-stm32@st-md-mailman.stormreply.com>,
        <linux-arm-kernel@lists.infradead.org>
References: <20220207165304.1046867-1-nathan@kernel.org>
From:   Raphael Gallais-Pou <raphael.gallais-pou@foss.st.com>
In-Reply-To: <20220207165304.1046867-1-nathan@kernel.org>
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Hello Nathan,


On 2/7/22 17:53, Nathan Chancellor wrote:
> Clang warns:
>
>   drivers/gpu/drm/stm/ltdc.c:625:2: warning: variable 'val' is used uninitialized whenever switch default is taken [-Wsometimes-uninitialized]
>           default:
>           ^~~~~~~
>   drivers/gpu/drm/stm/ltdc.c:635:2: note: uninitialized use occurs here
>           val |= LxPCR_YCEN;
>           ^~~
>   drivers/gpu/drm/stm/ltdc.c:600:9: note: initialize the variable 'val' to silence this warning
>           u32 val;
>                  ^
>                   = 0
>   1 warning generated.
>
> Use a return instead of break in the default case to fix the warning.
> Add an error message so that this return is not silent, which could hide
> issues in the future.
>
> Fixes: 484e72d3146b ("drm/stm: ltdc: add support of ycbcr pixel formats")
> Link: https://github.com/ClangBuiltLinux/linux/issues/1575
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> ---
>  drivers/gpu/drm/stm/ltdc.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)


Reviewed-by: Raphael Gallais-Pou <raphael.gallais-pou@foss.st.com>


Thanks,

Raphaël