Re: [PATCH v3] media: hantro: Implement support for encoder commands

[Ezequiel Garcia]

Hi Chen-Yu, Benjamin, Nicolas,

Sorry for the late review.

On Tue, Mar 01, 2022 at 12:22:25PM +0800, Chen-Yu Tsai wrote:
> The V4L2 stateful encoder uAPI specification requires that drivers
> support the ENCODER_CMD ioctl to allow draining of buffers. This
> however was not implemented, and causes issues for some userspace
> applications.
> 
> Implement support for the ENCODER_CMD ioctl using v4l2-mem2mem helpers.
> This is entirely based on existing code found in the vicodec test
> driver.
> 
> Fixes: 775fec69008d ("media: add Rockchip VPU JPEG encoder driver")
> Signed-off-by: Chen-Yu Tsai <wenst@xxxxxxxxxxxx>
> Reviewed-by: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxxxxx>
> ---
> 
> Changes since v2:
> - Dropped RFC tag
> - Added Reviewed-by from Benjamin
> - Replace direct access to vb->planes[i].bytesused with
>   vb2_set_plane_payload()
> 
> Changes since v1:
> - Correctly handle last buffers that are empty
> - Correctly handle last buffers that just got queued
> - Disable (TRY_)ENCODER_CMD ioctls for hantro decoder
> 
> This is based on linux-next-20220208, and was tested on RK3399 with
> Gstreamer running the JPEG encoder. It was also tested on ChromeOS
> 5.10 on Kevin with the video encoder used in ChromeOS ARC, which
> requires this. For ChromeOS, both encoder and decoder tests were run
> to check for regressions.
> 

Sounds great, thanks for running those tests!

> Everything really works OK now, but since I'm not very familiar with
> the mem2mem framework, I might be missing something, causing resource
> leaks. Hence this patch is labeled RFC.
> 

It would be great to apply this to a mainline-ish kernel,
and run some fluster and some stress-tests to ensure this is not
regressing decoding in some way.

> Last, I suppose we could also add support for (TRY_)DECODER_CMD now?
> 
>  drivers/staging/media/hantro/hantro_drv.c  | 17 +++++-
>  drivers/staging/media/hantro/hantro_v4l2.c | 68 +++++++++++++++++++++-
>  2 files changed, 81 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/staging/media/hantro/hantro_drv.c b/drivers/staging/media/hantro/hantro_drv.c
> index bc9bcb4eaf46..99bc650a5a93 100644
> --- a/drivers/staging/media/hantro/hantro_drv.c
> +++ b/drivers/staging/media/hantro/hantro_drv.c
> @@ -56,6 +56,10 @@ dma_addr_t hantro_get_ref(struct hantro_ctx *ctx, u64 ts)
>  	return hantro_get_dec_buf_addr(ctx, buf);
>  }
>  
> +static const struct v4l2_event hantro_eos_event = {
> +	.type = V4L2_EVENT_EOS
> +};
> +
>  static void hantro_job_finish_no_pm(struct hantro_dev *vpu,
>  				    struct hantro_ctx *ctx,
>  				    enum vb2_buffer_state result)
> @@ -73,6 +77,12 @@ static void hantro_job_finish_no_pm(struct hantro_dev *vpu,
>  	src->sequence = ctx->sequence_out++;
>  	dst->sequence = ctx->sequence_cap++;
>  
> +	if (v4l2_m2m_is_last_draining_src_buf(ctx->fh.m2m_ctx, src)) {
> +		dst->flags |= V4L2_BUF_FLAG_LAST;
> +		v4l2_event_queue_fh(&ctx->fh, &hantro_eos_event);
> +		v4l2_m2m_mark_stopped(ctx->fh.m2m_ctx);
> +	}
> +
>  	v4l2_m2m_buf_done_and_job_finish(ctx->dev->m2m_dev, ctx->fh.m2m_ctx,
>  					 result);
>  }
> @@ -807,10 +817,13 @@ static int hantro_add_func(struct hantro_dev *vpu, unsigned int funcid)
>  	snprintf(vfd->name, sizeof(vfd->name), "%s-%s", match->compatible,
>  		 funcid == MEDIA_ENT_F_PROC_VIDEO_ENCODER ? "enc" : "dec");
>  
> -	if (funcid == MEDIA_ENT_F_PROC_VIDEO_ENCODER)
> +	if (funcid == MEDIA_ENT_F_PROC_VIDEO_ENCODER) {
>  		vpu->encoder = func;
> -	else
> +	} else {
>  		vpu->decoder = func;
> +		v4l2_disable_ioctl(vfd, VIDIOC_TRY_ENCODER_CMD);
> +		v4l2_disable_ioctl(vfd, VIDIOC_ENCODER_CMD);
> +	}
>  
>  	video_set_drvdata(vfd, vpu);
>  
> diff --git a/drivers/staging/media/hantro/hantro_v4l2.c b/drivers/staging/media/hantro/hantro_v4l2.c
> index 67148ba346f5..aa10ecd04c9c 100644
> --- a/drivers/staging/media/hantro/hantro_v4l2.c
> +++ b/drivers/staging/media/hantro/hantro_v4l2.c
> @@ -628,6 +628,39 @@ static int vidioc_s_selection(struct file *file, void *priv,
>  	return 0;
>  }
>  
> +static const struct v4l2_event hantro_eos_event = {
> +	.type = V4L2_EVENT_EOS
> +};
> +
> +static int vidioc_encoder_cmd(struct file *file, void *priv,
> +			      struct v4l2_encoder_cmd *ec)
> +{
> +	struct hantro_ctx *ctx = fh_to_ctx(priv);
> +	int ret;
> +
> +	ret = v4l2_m2m_ioctl_try_encoder_cmd(file, priv, ec);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (!vb2_is_streaming(v4l2_m2m_get_src_vq(ctx->fh.m2m_ctx)) ||
> +	    !vb2_is_streaming(v4l2_m2m_get_dst_vq(ctx->fh.m2m_ctx)))
> +		return 0;
> +
> +	ret = v4l2_m2m_ioctl_encoder_cmd(file, priv, ec);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (ec->cmd == V4L2_ENC_CMD_STOP &&
> +	    v4l2_m2m_has_stopped(ctx->fh.m2m_ctx))
> +		v4l2_event_queue_fh(&ctx->fh, &hantro_eos_event);
> +
> +	if (ec->cmd == V4L2_ENC_CMD_START &&
> +	    v4l2_m2m_has_stopped(ctx->fh.m2m_ctx))

This looks odd. The has_stopped flag is cleared by calling
v4l2_m2m_ioctl_encoder_cmd so I can't see how it could be set here.

This same pattern is in the vicodec driver, the change was introduced
in d4d137de5f31d318ed9acdcdf359b9bd3920808b.

> +		vb2_clear_last_buffer_dequeued(&ctx->fh.m2m_ctx->cap_q_ctx.q);
> +
> +	return 0;
> +}
> +
>  const struct v4l2_ioctl_ops hantro_ioctl_ops = {
>  	.vidioc_querycap = vidioc_querycap,
>  	.vidioc_enum_framesizes = vidioc_enum_framesizes,
> @@ -657,6 +690,9 @@ const struct v4l2_ioctl_ops hantro_ioctl_ops = {
>  
>  	.vidioc_g_selection = vidioc_g_selection,
>  	.vidioc_s_selection = vidioc_s_selection,
> +
> +	.vidioc_try_encoder_cmd = v4l2_m2m_ioctl_try_encoder_cmd,
> +	.vidioc_encoder_cmd = vidioc_encoder_cmd,
>  };
>  
>  static int
> @@ -733,8 +769,12 @@ static int hantro_buf_prepare(struct vb2_buffer *vb)
>  	 * (for OUTPUT buffers, if userspace passes 0 bytesused, v4l2-core sets
>  	 * it to buffer length).
>  	 */
> -	if (V4L2_TYPE_IS_CAPTURE(vq->type))
> -		vb2_set_plane_payload(vb, 0, pix_fmt->plane_fmt[0].sizeimage);
> +	if (V4L2_TYPE_IS_CAPTURE(vq->type)) {
> +		if (ctx->is_encoder)
> +			vb2_set_plane_payload(vb, 0, 0);

This looks like some fix, that could be applied independently of this patch?

> +		else
> +			vb2_set_plane_payload(vb, 0, pix_fmt->plane_fmt[0].sizeimage);
> +	}
>  
>  	return 0;
>  }
> @@ -744,6 +784,22 @@ static void hantro_buf_queue(struct vb2_buffer *vb)
>  	struct hantro_ctx *ctx = vb2_get_drv_priv(vb->vb2_queue);
>  	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
>  
> +	if (V4L2_TYPE_IS_CAPTURE(vb->vb2_queue->type) &&
> +	    vb2_is_streaming(vb->vb2_queue) &&
> +	    v4l2_m2m_dst_buf_is_last(ctx->fh.m2m_ctx)) {
> +		unsigned int i;
> +
> +		for (i = 0; i < vb->num_planes; i++)
> +			vb2_set_plane_payload(vb, i, 0);
> +
> +		vbuf->field = V4L2_FIELD_NONE;
> +		vbuf->sequence = ctx->sequence_cap++;
> +
> +		v4l2_m2m_last_buffer_done(ctx->fh.m2m_ctx, vbuf);
> +		v4l2_event_queue_fh(&ctx->fh, &hantro_eos_event);
> +		return;
> +	}
> +
>  	v4l2_m2m_buf_queue(ctx->fh.m2m_ctx, vbuf);
>  }
>  
> @@ -759,6 +815,8 @@ static int hantro_start_streaming(struct vb2_queue *q, unsigned int count)
>  	struct hantro_ctx *ctx = vb2_get_drv_priv(q);
>  	int ret = 0;
>  
> +	v4l2_m2m_update_start_streaming_state(ctx->fh.m2m_ctx, q);
> +
>  	if (V4L2_TYPE_IS_OUTPUT(q->type))
>  		ctx->sequence_out = 0;
>  	else
> @@ -831,6 +889,12 @@ static void hantro_stop_streaming(struct vb2_queue *q)
>  		hantro_return_bufs(q, v4l2_m2m_src_buf_remove);
>  	else
>  		hantro_return_bufs(q, v4l2_m2m_dst_buf_remove);
> +
> +	v4l2_m2m_update_stop_streaming_state(ctx->fh.m2m_ctx, q);
> +
> +	if (V4L2_TYPE_IS_OUTPUT(q->type) &&
> +	    v4l2_m2m_has_stopped(ctx->fh.m2m_ctx))
> +		v4l2_event_queue_fh(&ctx->fh, &hantro_eos_event);
>  }
>  
>  static void hantro_buf_request_complete(struct vb2_buffer *vb)
> -- 
> 2.35.1.574.g5d30c73bfb-goog
> 

Thanks,
Ezequiel