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Message-ID: <1eb4cee6-85bb-4f99-ba77-c415522d6e93@xs4all.nl>
Date: Fri, 12 Apr 2024 16:19:28 +0200
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Subject: Re: [PATCH 1/3] media: dvb: as102-fe: Fix as10x_register_addr packing
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To: Ricardo Ribalda <ribalda@chromium.org>,
 Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20240410-pack-v1-0-70f287dd8a66@chromium.org>
 <20240410-pack-v1-1-70f287dd8a66@chromium.org>
From: Hans Verkuil <hverkuil-cisco@xs4all.nl>
In-Reply-To: <20240410-pack-v1-1-70f287dd8a66@chromium.org>
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On 10/04/2024 14:24, Ricardo Ribalda wrote:
> This structure is embedded in multiple other structures that are packed,
> which conflicts with it being aligned.
> 
> drivers/media/usb/as102/as10x_cmd.h:379:30: warning: field reg_addr within 'struct as10x_dump_memory::(unnamed at drivers/media/usb/as102/as10x_cmd.h:373:2)' is less aligned than 'struct as10x_register_addr' and is usually due to 'struct as10x_dump_memory::(unnamed at drivers/media/usb/as102/as10x_cmd.h:373:2)' being packed, which can lead to unaligned accesses [-Wunaligned-access]
> 
> Mark it as being packed.
> 
> Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
> ---
>  drivers/media/dvb-frontends/as102_fe_types.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/media/dvb-frontends/as102_fe_types.h b/drivers/media/dvb-frontends/as102_fe_types.h
> index 297f9520ebf9d..8a4e392c88965 100644
> --- a/drivers/media/dvb-frontends/as102_fe_types.h
> +++ b/drivers/media/dvb-frontends/as102_fe_types.h
> @@ -174,6 +174,6 @@ struct as10x_register_addr {
>  	uint32_t addr;
>  	/* register mode access */
>  	uint8_t mode;
> -};
> +} __packed;

Changing the layout of a struct is scary, but in this case I believe
as10x_register_addr isn't actually used in this driver at all.

So this looks OK.

Regards,

	Hans

>  
>  #endif
>