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From: Sergey Senozhatsky <senozhatsky@chromium.org>
To: Tomasz Figa <tfiga@chromium.org>,
	Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>,
	Dafna Hirschfeld <dafna.hirschfeld@collabora.com>,
	Ricardo Ribalda <ribalda@chromium.org>,
	Christoph Hellwig <hch@lst.de>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
	Sergey Senozhatsky <senozhatsky@chromium.org>
Subject: Re: [PATCHv6 7/8] videobuf2: handle V4L2_MEMORY_FLAG_NON_COHERENT flag
Date: Tue, 28 Sep 2021 13:50:44 +0900	[thread overview]
Message-ID: <YVKfJMpdHXrwYYRn@google.com> (raw)
In-Reply-To: <20210909112430.61243-8-senozhatsky@chromium.org>

On (21/09/09 20:24), Sergey Senozhatsky wrote:
[..]
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index 9b7032abb2c7..f118fe7a9f58 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -959,7 +959,8 @@ struct v4l2_requestbuffers {
>  	__u32			type;		/* enum v4l2_buf_type */
>  	__u32			memory;		/* enum v4l2_memory */
>  	__u32			capabilities;
> -	__u32			reserved[1];
> +	__u8			flags;
> +	__u8			reserved[3];
>  };

[..]

>  struct v4l2_create_buffers {
> @@ -2515,7 +2519,8 @@ struct v4l2_create_buffers {
>  	__u32			memory;
>  	struct v4l2_format	format;
>  	__u32			capabilities;
> -	__u32			reserved[7];
> +	__u32			flags;
> +	__u32			reserved[6];
>  };

These UAPI changes break strace compilation (older versions). Up until
Feb 2021 strace had compile time asserts that check-ed sizeof() ->reserved
fields.

  static_assert failed due to requirement
   '(sizeof (((struct v4l2_create_buffers *)0)->reserved)) >= (sizeof (((struct_v4l2_create_buffers *)0)->reserved))'
   "Unexpected struct v4l2_create_buffers.reserved size, please update the decoder"

It seems that strace has dropped those assertions

https://github.com/strace/strace/commit/e5554291d14b852f61385ba5ba59412d133ac99d#diff-d534423e8a79b6957ef4deb7f8bbd3276bf18ede6a82553e8823ee4f840b6e06


But we, probably, need to use unions in UAPI. Any thoughts?

  reply	other threads:[~2021-09-28  4:50 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-09 11:24 [PATCHv6 0/8] videobuf2: support new noncontiguous DMA API Sergey Senozhatsky
2021-09-09 11:24 ` [PATCHv6 1/8] videobuf2: rework vb2_mem_ops API Sergey Senozhatsky
2021-09-09 11:24 ` [PATCHv6 2/8] videobuf2: inverse buffer cache_hints flags Sergey Senozhatsky
2021-09-28  6:05   ` Chen-Yu Tsai
2021-09-09 11:24 ` [PATCHv6 3/8] videobuf2: split buffer cache_hints initialisation Sergey Senozhatsky
2021-09-09 11:24 ` [PATCHv6 4/8] videobuf2: move cache_hints handling to allocators Sergey Senozhatsky
2021-09-09 11:24 ` [PATCHv6 5/8] videobuf2: add V4L2_MEMORY_FLAG_NON_COHERENT flag Sergey Senozhatsky
2021-09-09 11:24 ` [PATCHv6 6/8] videobuf2: add queue memory coherency parameter Sergey Senozhatsky
2021-09-09 11:24 ` [PATCHv6 7/8] videobuf2: handle V4L2_MEMORY_FLAG_NON_COHERENT flag Sergey Senozhatsky
2021-09-28  4:50   ` Sergey Senozhatsky [this message]
2021-09-09 11:24 ` [PATCHv6 8/8] videobuf2: handle non-contiguous DMA allocations Sergey Senozhatsky
2021-09-10 10:00 ` [PATCHv6 0/8] videobuf2: support new noncontiguous DMA API Tomasz Figa

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