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Message-ID: <9d44d2136ba60e7471ea82551f4cfed2c030ce2b.camel@ndufresne.ca>
Subject: Re: [PATCH v7, 05/15] media: mtk-vcodec: Call
 v4l2_m2m_set_dst_buffered() set capture buffer buffered
From:   Nicolas Dufresne <nicolas@ndufresne.ca>
To:     Yunfei Dong <yunfei.dong@mediatek.com>,
        Alexandre Courbot <acourbot@chromium.org>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Tzung-Bi Shih <tzungbi@chromium.org>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>,
        Benjamin Gaignard <benjamin.gaignard@collabora.com>,
        Tiffany Lin <tiffany.lin@mediatek.com>,
        Andrew-CT Chen <andrew-ct.chen@mediatek.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Tomasz Figa <tfiga@google.com>
Cc:     George Sun <george.sun@mediatek.com>,
        Xiaoyong Lu <xiaoyong.lu@mediatek.com>,
        Hsin-Yi Wang <hsinyi@chromium.org>,
        Fritz Koenig <frkoenig@chromium.org>,
        Dafna Hirschfeld <dafna.hirschfeld@collabora.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        Irui Wang <irui.wang@mediatek.com>,
        Steve Cho <stevecho@chromium.org>, linux-media@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, srv_heupstream@mediatek.com,
        linux-mediatek@lists.infradead.org,
        Project_Global_Chrome_Upstream_Group@mediatek.com
Date:   Tue, 01 Mar 2022 13:50:03 -0500
In-Reply-To: <20220223034008.15781-6-yunfei.dong@mediatek.com>
References: <20220223034008.15781-1-yunfei.dong@mediatek.com>
         <20220223034008.15781-6-yunfei.dong@mediatek.com>
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Le mercredi 23 février 2022 à 11:39 +0800, Yunfei Dong a écrit :
> lat thread: output queue      \
>                                -> lat hardware -> lat trans buffer
>             lat trans buffer  /
> 
> core thread: capture queue     \
>                                 ->core hardware -> capture queue
>              lat trans buffer  /
> 
> Lat and core work in different thread, setting capture buffer buffered.

... so that output queue buffers (bitstream) can be process regardless if there
is available capture buffers.

I have concerns around the usefulness of running a dedicated thread to drive the
lat and the core blocks. Having 3 threads (counting the m2m worker thread) here
increase the complexity. The hardware is asynchronous by definition. I think
this patch will go away after a proper rework of the driver thread model here.

> 
> Signed-off-by: Yunfei Dong <yunfei.dong@mediatek.com>
> ---
>  drivers/media/platform/mtk-vcodec/mtk_vcodec_dec_stateless.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/media/platform/mtk-vcodec/mtk_vcodec_dec_stateless.c b/drivers/media/platform/mtk-vcodec/mtk_vcodec_dec_stateless.c
> index 5aebf88f997b..23a154c4e321 100644
> --- a/drivers/media/platform/mtk-vcodec/mtk_vcodec_dec_stateless.c
> +++ b/drivers/media/platform/mtk-vcodec/mtk_vcodec_dec_stateless.c
> @@ -314,6 +314,9 @@ static void mtk_init_vdec_params(struct mtk_vcodec_ctx *ctx)
>  	src_vq = v4l2_m2m_get_vq(ctx->m2m_ctx,
>  				 V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE);
>  
> +	if (ctx->dev->vdec_pdata->hw_arch != MTK_VDEC_PURE_SINGLE_CORE)
> +		v4l2_m2m_set_dst_buffered(ctx->m2m_ctx, 1);
> +
>  	/* Support request api for output plane */
>  	src_vq->supports_requests = true;
>  	src_vq->requires_requests = true;