Subject: Re: [PATCH 7/8] media: cedrus: Add support for holding capture buffer

From: Boris Brezillon <[email-masked]>
Date: Mon, 26 Aug 2019 20:38:29 +0200

On Thu, 22 Aug 2019 21:44:59 +0200
Jernej Skrabec <[email-masked]> wrote:

> When frame contains multiple slices and driver works in slice mode, it's
> more efficient to hold capture buffer in queue until all slices of a
> same frame are decoded.
> 
> Add support for that to Cedrus driver by exposing and implementing
> V4L2_BUF_CAP_SUPPORTS_M2M_HOLD_CAPTURE_BUF capability.
> 
> Signed-off-by: Jernej Skrabec <[email-masked]>

Reviewed-by: Boris Brezillon <[email-masked]>

> ---
>  drivers/staging/media/sunxi/cedrus/cedrus_dec.c   | 9 +++++++++
>  drivers/staging/media/sunxi/cedrus/cedrus_hw.c    | 8 +++++---
>  drivers/staging/media/sunxi/cedrus/cedrus_video.c | 1 +
>  3 files changed, 15 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_dec.c b/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
> index d7b54accfe83..68462b99750e 100644
> --- a/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
> +++ b/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
> @@ -31,6 +31,14 @@ void cedrus_device_run(void *priv)
>  
>  	run.src = v4l2_m2m_next_src_buf(ctx->fh.m2m_ctx);
>  	run.dst = v4l2_m2m_next_dst_buf(ctx->fh.m2m_ctx);
> +
> +	if (v4l2_m2m_release_capture_buf(run.src, run.dst)) {
> +		v4l2_m2m_dst_buf_remove(ctx->fh.m2m_ctx);
> +		v4l2_m2m_buf_done(run.dst, VB2_BUF_STATE_DONE);
> +		run.dst = v4l2_m2m_next_dst_buf(ctx->fh.m2m_ctx);
> +	}
> +	run.dst->is_held = run.src->flags & V4L2_BUF_FLAG_M2M_HOLD_CAPTURE_BUF;
> +
>  	run.first_slice =
>  		run.src->vb2_buf.timestamp != run.dst->vb2_buf.timestamp;
>  
> @@ -46,6 +54,7 @@ void cedrus_device_run(void *priv)
>  			V4L2_CID_MPEG_VIDEO_MPEG2_SLICE_PARAMS);
>  		run.mpeg2.quantization = cedrus_find_control_data(ctx,
>  			V4L2_CID_MPEG_VIDEO_MPEG2_QUANTIZATION);
> +		run.dst->is_held = false;
>  		break;
>  
>  	case V4L2_PIX_FMT_H264_SLICE:
> diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_hw.c b/drivers/staging/media/sunxi/cedrus/cedrus_hw.c
> index a942cd9bed57..99fedec80224 100644
> --- a/drivers/staging/media/sunxi/cedrus/cedrus_hw.c
> +++ b/drivers/staging/media/sunxi/cedrus/cedrus_hw.c
> @@ -122,7 +122,7 @@ static irqreturn_t cedrus_irq(int irq, void *data)
>  	dev->dec_ops[ctx->current_codec]->irq_clear(ctx);
>  
>  	src_buf = v4l2_m2m_src_buf_remove(ctx->fh.m2m_ctx);
> -	dst_buf = v4l2_m2m_dst_buf_remove(ctx->fh.m2m_ctx);
> +	dst_buf = v4l2_m2m_next_dst_buf(ctx->fh.m2m_ctx);
>  
>  	if (!src_buf || !dst_buf) {
>  		v4l2_err(&dev->v4l2_dev,
> @@ -136,8 +136,10 @@ static irqreturn_t cedrus_irq(int irq, void *data)
>  		state = VB2_BUF_STATE_DONE;
>  
>  	v4l2_m2m_buf_done(src_buf, state);
> -	v4l2_m2m_buf_done(dst_buf, state);
> -
> +	if (!dst_buf->is_held) {
> +		v4l2_m2m_dst_buf_remove(ctx->fh.m2m_ctx);
> +		v4l2_m2m_buf_done(dst_buf, state);
> +	}
>  	v4l2_m2m_job_finish(ctx->dev->m2m_dev, ctx->fh.m2m_ctx);
>  
>  	return IRQ_HANDLED;
> diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_video.c b/drivers/staging/media/sunxi/cedrus/cedrus_video.c
> index eeee3efd247b..5153b2bba21e 100644
> --- a/drivers/staging/media/sunxi/cedrus/cedrus_video.c
> +++ b/drivers/staging/media/sunxi/cedrus/cedrus_video.c
> @@ -515,6 +515,7 @@ int cedrus_queue_init(void *priv, struct vb2_queue *src_vq,
>  	src_vq->type = V4L2_BUF_TYPE_VIDEO_OUTPUT;
>  	src_vq->io_modes = VB2_MMAP | VB2_DMABUF;
>  	src_vq->drv_priv = ctx;
> +	src_vq->subsystem_flags = VB2_V4L2_FL_SUPPORTS_M2M_HOLD_CAPTURE_BUF;
>  	src_vq->buf_struct_size = sizeof(struct cedrus_buffer);
>  	src_vq->min_buffers_needed = 1;
>  	src_vq->ops = &cedrus_qops;

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