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Message-ID: <edd368ea3cc9bb31700600a7f1fe7c837501458c.camel@collabora.com>
Subject: Re: [PATCH] media: v4l2-mem2mem: allow device run without buf
From:   Nicolas Dufresne <nicolas.dufresne@collabora.com>
To:     Hsia-Jun Li <randy.li@synaptics.com>, linux-media@vger.kernel.org
Cc:     mchehab@kernel.org, hverkuil-cisco@xs4all.nl,
        sebastian.fricke@collabora.com,
        kieran.bingham+renesas@ideasonboard.com,
        laurent.pinchart@ideasonboard.com, ming.qian@nxp.com,
        wenst@chromium.org, linux-kernel@vger.kernel.org,
        Randy Li <ayaka@soulik.info>
Date:   Fri, 25 Nov 2022 08:43:15 -0500
In-Reply-To: <20221123092427.76055-1-randy.li@synaptics.com>
References: <20221123092427.76055-1-randy.li@synaptics.com>
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Le mercredi 23 novembre 2022 =C3=A0 17:24 +0800, Hsia-Jun Li a =C3=A9crit=
=C2=A0:
> From: Randy Li <ayaka@soulik.info>
>=20
> For the decoder supports Dynamic Resolution Change,
> we don't need to allocate any CAPTURE or graphics buffer
> for them at inital CAPTURE setup step.
>=20
> We need to make the device run or we can't get those
> metadata.

Nack: This is not how it works. I know the m2m framework make it difficult,=
 but
it is expected that the driver have a special state for OUTPUT streamon (be=
fore
capture streamon). Please have a look at other drivers.

Nicolas

>=20
> Signed-off-by: Randy Li <ayaka@soulik.info>
> ---
>  drivers/media/v4l2-core/v4l2-mem2mem.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>=20
> diff --git a/drivers/media/v4l2-core/v4l2-mem2mem.c b/drivers/media/v4l2-=
core/v4l2-mem2mem.c
> index be7fde1ed3ea..cd56d60fad9d 100644
> --- a/drivers/media/v4l2-core/v4l2-mem2mem.c
> +++ b/drivers/media/v4l2-core/v4l2-mem2mem.c
> @@ -301,8 +301,9 @@ static void __v4l2_m2m_try_queue(struct v4l2_m2m_dev =
*m2m_dev,
> =20
>  	dprintk("Trying to schedule a job for m2m_ctx: %p\n", m2m_ctx);
> =20
> -	if (!m2m_ctx->out_q_ctx.q.streaming
> -	    || !m2m_ctx->cap_q_ctx.q.streaming) {
> +	if (!(m2m_ctx->out_q_ctx.q.streaming || m2m_ctx->out_q_ctx.buffered)
> +	    || !(m2m_ctx->cap_q_ctx.q.streaming
> +		 || m2m_ctx->cap_q_ctx.buffered)) {
>  		dprintk("Streaming needs to be on for both queues\n");
>  		return;
>  	}