Re: [PATCH v2 6/6] media: cedrus: Add support for holding capture buffer

[Hans Verkuil]

On 9/29/19 10:00 PM, Jernej Skrabec 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 <jernej.skrabec@xxxxxxxx>
> ---
>  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 | 14 ++++++++++++++
>  3 files changed, 28 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_dec.c b/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
> index e49c3396ca4d..67f7d4326fc1 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.dst->vb2_buf.copied_timestamp ||
>  		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 fc8579b90dab..b466041c25db 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 3ec3a2db790c..82198b2bb081 100644
> --- a/drivers/staging/media/sunxi/cedrus/cedrus_video.c
> +++ b/drivers/staging/media/sunxi/cedrus/cedrus_video.c
> @@ -303,6 +303,17 @@ static int cedrus_s_fmt_vid_out(struct file *file, void *priv,
>  
>  	ctx->src_fmt = f->fmt.pix;
>  
> +	switch (ctx->src_fmt.pixelformat) {
> +	case V4L2_PIX_FMT_H264_SLICE:
> +		vq->subsystem_flags |=
> +			VB2_V4L2_FL_SUPPORTS_M2M_HOLD_CAPTURE_BUF;
> +		break;
> +	default:
> +		vq->subsystem_flags &=
> +			(u32)~VB2_V4L2_FL_SUPPORTS_M2M_HOLD_CAPTURE_BUF;

Why the u32 cast?

Regards,

	Hans

> +		break;
> +	}
> +
>  	/* Propagate colorspace information to capture. */
>  	ctx->dst_fmt.colorspace = f->fmt.pix.colorspace;
>  	ctx->dst_fmt.xfer_func = f->fmt.pix.xfer_func;
> @@ -336,6 +347,9 @@ const struct v4l2_ioctl_ops cedrus_ioctl_ops = {
>  	.vidioc_streamon		= v4l2_m2m_ioctl_streamon,
>  	.vidioc_streamoff		= v4l2_m2m_ioctl_streamoff,
>  
> +	.vidioc_try_decoder_cmd		= v4l2_m2m_ioctl_stateless_try_decoder_cmd,
> +	.vidioc_decoder_cmd		= v4l2_m2m_ioctl_stateless_decoder_cmd,
> +
>  	.vidioc_subscribe_event		= v4l2_ctrl_subscribe_event,
>  	.vidioc_unsubscribe_event	= v4l2_event_unsubscribe,
>  };
>