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Date:   Thu, 12 Jan 2023 13:35:26 +0000
From:   Sakari Ailus <sakari.ailus@linux.intel.com>
To:     Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Cc:     linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        Jacopo Mondi <jacopo+renesas@jmondi.org>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        niklas.soderlund+renesas@ragnatech.se,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        satish.nagireddy@getcruise.com, Tomasz Figa <tfiga@chromium.org>
Subject: Re: [PATCH v16 06/20] media: subdev: Require code change to enable
 [GS]_ROUTING
Message-ID: <Y8AMns140Eq3S7ER@paasikivi.fi.intel.com>
References: <20221215121634.287100-1-tomi.valkeinen@ideasonboard.com>
 <20221215121634.287100-7-tomi.valkeinen@ideasonboard.com>
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In-Reply-To: <20221215121634.287100-7-tomi.valkeinen@ideasonboard.com>
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Moi,

On Thu, Dec 15, 2022 at 02:16:20PM +0200, Tomi Valkeinen wrote:
> Streams API is an experimental feature. To use Streams API, the user
> needs to change a variable in v4l2-subdev.c and recompile the kernel.
> 
> This commit should be reverted when the Streams API is deemed ready for
> production use.
> 
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> ---
>  drivers/media/v4l2-core/v4l2-subdev.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> index 61b429016a2f..c31b44800e39 100644
> --- a/drivers/media/v4l2-core/v4l2-subdev.c
> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> @@ -23,6 +23,13 @@
>  #include <media/v4l2-fh.h>
>  #include <media/v4l2-ioctl.h>
>  
> +/*
> + * Streams API is an experimental feature. To use Streams API, set
> + * 'v4l2_subdev_enable_streams_api' to 1 below.
> + */
> +
> +static bool v4l2_subdev_enable_streams_api = 0;

Static variables shouldn't be explicitly assigned to zero. I'll address
this while applying.

> +
>  /*
>   * Maximum stream ID is 63 for now, as we use u64 bitmask to represent a set
>   * of streams.
> @@ -751,6 +758,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg,
>  		struct v4l2_subdev_routing *routing = arg;
>  		struct v4l2_subdev_krouting *krouting;
>  
> +		if (!v4l2_subdev_enable_streams_api)
> +			return -ENOIOCTLCMD;
> +
>  		if (!(sd->flags & V4L2_SUBDEV_FL_STREAMS))
>  			return -ENOIOCTLCMD;
>  
> @@ -778,6 +788,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg,
>  		struct v4l2_subdev_krouting krouting = {};
>  		unsigned int i;
>  
> +		if (!v4l2_subdev_enable_streams_api)
> +			return -ENOIOCTLCMD;
> +
>  		if (!(sd->flags & V4L2_SUBDEV_FL_STREAMS))
>  			return -ENOIOCTLCMD;
>  

-- 
Terveisin,

Sakari Ailus