Re: [PATCH] media: rkvdec: vp9: Fix probs struct alignment

[Nicolas Dufresne <nicolas.dufresne@collabora.com>]

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Le vendredi 12 décembre 2025 à 11:01 -0500, Detlev Casanova a écrit :
> When building for arm 32 bits, the struct alignment changes and the compiler
> adds 3 padding bits to the anonymous mv struct in
> rkvdec_vp9_inter_frame_probs.
> 
> Therefore, the BUILD_BUG_ON used to check that the struct size is aligned
> to 128 bits (hardware requirement) fails.
> 
> As that mv struct is at the end of the global rkvdec_vp9_probs struct
> and is followed by 11 padding bits, the 3 padding bits can be explicitely
> set in the mv struct and removed from the 11 following it.
> 
> This makes sure that the mv struct is 32 bits aligned.
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Closes:
> https://lore.kernel.org/oe-kbuild-all/202512110229.R6YCf1Le-lkp@intel.com/
> Fixes: d968e50b5c26 ("media: rkvdec: Unstage the driver")
> Suggested-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
> Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>

Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>

> ---
>  drivers/media/platform/rockchip/rkvdec/rkvdec-vp9.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/platform/rockchip/rkvdec/rkvdec-vp9.c
> b/drivers/media/platform/rockchip/rkvdec/rkvdec-vp9.c
> index b4bf01e839ef..23c733ca2e8e 100644
> --- a/drivers/media/platform/rockchip/rkvdec/rkvdec-vp9.c
> +++ b/drivers/media/platform/rockchip/rkvdec/rkvdec-vp9.c
> @@ -66,6 +66,8 @@ struct rkvdec_vp9_inter_frame_probs {
>  		u8 fr[2][3];
>  		u8 class0_hp[2];
>  		u8 hp[2];
> +		/* 32 bit alignment */
> +		u8 padding6[3];
>  	} mv;
>  };
>  
> @@ -85,7 +87,7 @@ struct rkvdec_vp9_probs {
>  		struct rkvdec_vp9_intra_only_frame_probs intra_only;
>  	};
>  	/* 128 bit alignment */
> -	u8 padding1[11];
> +	u8 padding1[8];
>  };
>  
>  /* Data structure describing auxiliary buffer format. */

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