Date: Thu, 21 Dec 2017 16:17:48 -0200
From: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
To: Gustavo Padovan <gustavo@padovan.org>
Cc: linux-media@vger.kernel.org, Hans Verkuil <hverkuil@xs4all.nl>,
        Shuah Khan <shuahkh@osg.samsung.com>, Pawel Osciak <pawel@osciak.com>,
        Alexandre Courbot <acourbot@chromium.org>,
        Sakari Ailus <sakari.ailus@iki.fi>,
        Brian Starkey <brian.starkey@arm.com>,
        Thierry Escande <thierry.escande@collabora.com>,
        linux-kernel@vger.kernel.org,
        Gustavo Padovan <gustavo.padovan@collabora.com>
Subject: Re: [PATCH v6 2/6] [media] v4l: add 'unordered' flag to format
 description ioctl
Message-ID: <20171221161748.71a8f42e@vento.lan>
In-Reply-To: <20171211182741.29712-3-gustavo@padovan.org>
References: <20171211182741.29712-1-gustavo@padovan.org>
        <20171211182741.29712-3-gustavo@padovan.org>
Organization: Samsung
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1814
Lines: 52

Em Mon, 11 Dec 2017 16:27:37 -0200
Gustavo Padovan <gustavo@padovan.org> escreveu:

> From: Gustavo Padovan <gustavo.padovan@collabora.com>
> 
> For explicit synchronization it important for userspace to know if the
> format being used by the driver can deliver the buffers back to userspace
> in the same order they were queued with QBUF.
> 
> Ordered streams fits nicely in a pipeline with DRM for example, where
> ordered buffer are expected.
> 
> Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>

Looks OK to me.

> ---
>  Documentation/media/uapi/v4l/vidioc-enum-fmt.rst | 3 +++
>  include/uapi/linux/videodev2.h                   | 1 +
>  2 files changed, 4 insertions(+)
> 
> diff --git a/Documentation/media/uapi/v4l/vidioc-enum-fmt.rst b/Documentation/media/uapi/v4l/vidioc-enum-fmt.rst
> index 019c513df217..368115f44fc0 100644
> --- a/Documentation/media/uapi/v4l/vidioc-enum-fmt.rst
> +++ b/Documentation/media/uapi/v4l/vidioc-enum-fmt.rst
> @@ -116,6 +116,9 @@ one until ``EINVAL`` is returned.
>        - This format is not native to the device but emulated through
>  	software (usually libv4l2), where possible try to use a native
>  	format instead for better performance.
> +    * - ``V4L2_FMT_FLAG_UNORDERED``
> +      - 0x0004
> +      - This is a format that doesn't guarantee timely order of frames.
>  
>  
>  Return Value
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index 1c095b5a99c5..a8ea632c14f0 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -709,6 +709,7 @@ struct v4l2_fmtdesc {
>  
>  #define V4L2_FMT_FLAG_COMPRESSED 0x0001
>  #define V4L2_FMT_FLAG_EMULATED   0x0002
> +#define V4L2_FMT_FLAG_UNORDERED  0x0004
>  
>  	/* Frame Size and frame rate enumeration */
>  /*


-- 
Thanks,
Mauro