Re: [RFC PATCH v9 1/6] media: videobuf2: Move timestamp to vb2_buffer

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Dear Hans,

First of all, thank you for your review.

On 11/04/2015 09:28 PM, Hans Verkuil wrote:
On 11/03/15 11:16, Junghak Sung wrote:
Move timestamp from struct vb2_v4l2_buffer to struct vb2_buffer
for common use, and change its type to u64 in order to handling
y2038 problem. This patch also includes all device drivers' changes related to
this restructuring.

Signed-off-by: Junghak Sung <jh1009.sung@xxxxxxxxxxx>
Signed-off-by: Geunyoung Kim <nenggun.kim@xxxxxxxxxxx>
Acked-by: Seung-Woo Kim <sw0312.kim@xxxxxxxxxxx>
Acked-by: Inki Dae <inki.dae@xxxxxxxxxxx>
---

<snip>

diff --git a/drivers/media/pci/solo6x10/solo6x10-v4l2-enc.c b/drivers/media/pci/solo6x10/solo6x10-v4l2-enc.c
index 1bd2fd4..61df3e4 100644
--- a/drivers/media/pci/solo6x10/solo6x10-v4l2-enc.c
+++ b/drivers/media/pci/solo6x10/solo6x10-v4l2-enc.c
@@ -531,8 +531,8 @@ static int solo_enc_fillbuf(struct solo_enc_dev *solo_enc,

  	if (!ret) {
  		vbuf->sequence = solo_enc->sequence++;
-		vbuf->timestamp.tv_sec = vop_sec(vh);
-		vbuf->timestamp.tv_usec = vop_usec(vh);
+		vb->timestamp = ((u64) vop_sec(vh) * NSEC_PER_SEC) +
+				(vop_usec(vh) * NSEC_PER_USEC);

This is wrong. Just use ktime_get_ns() here. It is probably best to first make a
single patch to change the solo driver to use v4l2_get_timestamp(), then convert
that to ktime_get_ns() in this patch.

The problem is that the timestamp is taken from the mpeg header, and so it is
not a CLOCK_MONOTONIC timestamp as is signaled to the user. Never noticed this
before, but it is a solo driver bug.

OK, I will prepare a single patch for solo driver to use
v4l2_get_timestamp(), and then converting to ktime_get_ns()
will be included in next version - v10.
I'm not aware of this historical problem.
so, it's very helpful. Thank you, Hans.



  		/* Check for motion flags */
  		if (solo_is_motion_on(solo_enc) && enc_buf->motion) {
diff --git a/drivers/media/pci/solo6x10/solo6x10-v4l2.c b/drivers/media/pci/solo6x10/solo6x10-v4l2.c
index 26df903..44b00b8 100644
--- a/drivers/media/pci/solo6x10/solo6x10-v4l2.c
+++ b/drivers/media/pci/solo6x10/solo6x10-v4l2.c
@@ -225,7 +225,7 @@ finish_buf:
  		vb2_set_plane_payload(vb, 0,
  			solo_vlines(solo_dev) * solo_bytesperline(solo_dev));
  		vbuf->sequence = solo_dev->sequence++;
-		v4l2_get_timestamp(&vbuf->timestamp);
+		vb->timestamp = ktime_get_ns();
  	}

  	vb2_buffer_done(vb, error ? VB2_BUF_STATE_ERROR : VB2_BUF_STATE_DONE);

<snip>

diff --git a/drivers/media/platform/vivid/vivid-kthread-cap.c b/drivers/media/platform/vivid/vivid-kthread-cap.c
index 83cc6d3..b0ad054 100644
--- a/drivers/media/platform/vivid/vivid-kthread-cap.c
+++ b/drivers/media/platform/vivid/vivid-kthread-cap.c
@@ -441,7 +441,7 @@ static void vivid_fillbuff(struct vivid_dev *dev, struct vivid_buffer *buf)
  	 * "Start of Exposure".
  	 */
  	if (dev->tstamp_src_is_soe)
-		v4l2_get_timestamp(&buf->vb.timestamp);
+		buf->vb.vb2_buf.timestamp = ktime_get_ns();
  	if (dev->field_cap == V4L2_FIELD_ALTERNATE) {
  		/*
  		 * 60 Hz standards start with the bottom field, 50 Hz standards
@@ -558,8 +558,9 @@ static void vivid_fillbuff(struct vivid_dev *dev, struct vivid_buffer *buf)
  	 * the timestamp now.
  	 */
  	if (!dev->tstamp_src_is_soe)
-		v4l2_get_timestamp(&buf->vb.timestamp);
-	buf->vb.timestamp.tv_sec += dev->time_wrap_offset;
+		buf->vb.vb2_buf.timestamp = ktime_get_ns();
+	buf->vb.vb2_buf.timestamp +=
+			((u64) dev->time_wrap_offset * NSEC_PER_SEC);

I'd do this differently: make time_wrap_offset of type u64 and assign it
accordingly with nanoseconds. That way you can just do:

	timestamp += dev->time_wrap_offset

vivid-ctrls.c also needs to be modified (vivid_streaming_s_ctrl(), VIVID_CID_TIME_WRAP
case) to:

	dev->time_wrap_offset = (0x100000000ULL - 16) * NSEC_PER_SEC - ktime_get_ns();

The v4l2_get_timestamp() call there can be dropped.


I agree with your opinion. But it is too hard to read the code
getting time_wrap_offset.
How about this way?

 in vivid_streaming_s_ctrl() of vivid-ctrls.c
        dev->time_wrap_offset = ktime_get_ns() + 16 * NSEC_PER_SEC;
 and in vivid_fillbuff() of vivid-kthread-cap.c
	buf->vb.vb2_buf.timestamp -= dev->time_wrap_offset;


  }

  /*
diff --git a/drivers/media/platform/vivid/vivid-kthread-out.c b/drivers/media/platform/vivid/vivid-kthread-out.c
index c2c46dc..6fd02c9 100644
--- a/drivers/media/platform/vivid/vivid-kthread-out.c
+++ b/drivers/media/platform/vivid/vivid-kthread-out.c
@@ -95,8 +95,9 @@ static void vivid_thread_vid_out_tick(struct vivid_dev *dev)
  			 */
  			vid_out_buf->vb.sequence /= 2;
  		}
-		v4l2_get_timestamp(&vid_out_buf->vb.timestamp);
-		vid_out_buf->vb.timestamp.tv_sec += dev->time_wrap_offset;
+		vid_out_buf->vb.vb2_buf.timestamp = ktime_get_ns();
+		vid_out_buf->vb.vb2_buf.timestamp +=
+				((u64) dev->time_wrap_offset * NSEC_PER_SEC);
  		vb2_buffer_done(&vid_out_buf->vb.vb2_buf, dev->dqbuf_error ?
  				VB2_BUF_STATE_ERROR : VB2_BUF_STATE_DONE);
  		dprintk(dev, 2, "vid_out buffer %d done\n",
@@ -108,8 +109,9 @@ static void vivid_thread_vid_out_tick(struct vivid_dev *dev)
  			vivid_sliced_vbi_out_process(dev, vbi_out_buf);

  		vbi_out_buf->vb.sequence = dev->vbi_out_seq_count;
-		v4l2_get_timestamp(&vbi_out_buf->vb.timestamp);
-		vbi_out_buf->vb.timestamp.tv_sec += dev->time_wrap_offset;
+		vbi_out_buf->vb.vb2_buf.timestamp = ktime_get_ns();
+		vbi_out_buf->vb.vb2_buf.timestamp +=
+				((u64) dev->time_wrap_offset * NSEC_PER_SEC);
  		vb2_buffer_done(&vbi_out_buf->vb.vb2_buf, dev->dqbuf_error ?
  				VB2_BUF_STATE_ERROR : VB2_BUF_STATE_DONE);
  		dprintk(dev, 2, "vbi_out buffer %d done\n",
diff --git a/drivers/media/platform/vivid/vivid-sdr-cap.c b/drivers/media/platform/vivid/vivid-sdr-cap.c
index 082c401..dbdb43d 100644
--- a/drivers/media/platform/vivid/vivid-sdr-cap.c
+++ b/drivers/media/platform/vivid/vivid-sdr-cap.c
@@ -117,8 +117,9 @@ static void vivid_thread_sdr_cap_tick(struct vivid_dev *dev)
  	if (sdr_cap_buf) {
  		sdr_cap_buf->vb.sequence = dev->sdr_cap_seq_count;
  		vivid_sdr_cap_process(dev, sdr_cap_buf);
-		v4l2_get_timestamp(&sdr_cap_buf->vb.timestamp);
-		sdr_cap_buf->vb.timestamp.tv_sec += dev->time_wrap_offset;
+		sdr_cap_buf->vb.vb2_buf.timestamp = ktime_get_ns();
+		sdr_cap_buf->vb.vb2_buf.timestamp +=
+				((u64) dev->time_wrap_offset * NSEC_PER_SEC);
  		vb2_buffer_done(&sdr_cap_buf->vb.vb2_buf, dev->dqbuf_error ?
  				VB2_BUF_STATE_ERROR : VB2_BUF_STATE_DONE);
  		dev->dqbuf_error = false;
diff --git a/drivers/media/platform/vivid/vivid-vbi-cap.c b/drivers/media/platform/vivid/vivid-vbi-cap.c
index e903d02..2f5f330 100644
--- a/drivers/media/platform/vivid/vivid-vbi-cap.c
+++ b/drivers/media/platform/vivid/vivid-vbi-cap.c
@@ -108,8 +108,9 @@ void vivid_raw_vbi_cap_process(struct vivid_dev *dev, struct vivid_buffer *buf)
  	if (!VIVID_INVALID_SIGNAL(dev->std_signal_mode))
  		vivid_vbi_gen_raw(&dev->vbi_gen, &vbi, vbuf);

-	v4l2_get_timestamp(&buf->vb.timestamp);
-	buf->vb.timestamp.tv_sec += dev->time_wrap_offset;
+	buf->vb.vb2_buf.timestamp = ktime_get_ns();
+	buf->vb.vb2_buf.timestamp +=
+			((u64) dev->time_wrap_offset * NSEC_PER_SEC);
  }


@@ -133,8 +134,9 @@ void vivid_sliced_vbi_cap_process(struct vivid_dev *dev,
  			vbuf[i] = dev->vbi_gen.data[i];
  	}

-	v4l2_get_timestamp(&buf->vb.timestamp);
-	buf->vb.timestamp.tv_sec += dev->time_wrap_offset;
+	buf->vb.vb2_buf.timestamp = ktime_get_ns();
+	buf->vb.vb2_buf.timestamp +=
+			((u64) dev->time_wrap_offset * NSEC_PER_SEC);
  }

  static int vbi_cap_queue_setup(struct vb2_queue *vq, const void *parg,

<snip>

diff --git a/drivers/media/v4l2-core/videobuf2-v4l2.c b/drivers/media/v4l2-core/videobuf2-v4l2.c
index 27b4b9e..93e16375 100644
--- a/drivers/media/v4l2-core/videobuf2-v4l2.c
+++ b/drivers/media/v4l2-core/videobuf2-v4l2.c
@@ -119,8 +119,9 @@ static int __set_timestamp(struct vb2_buffer *vb, const void *pb)
  		 * and the timecode field and flag if needed.
  		 */
  		if ((q->timestamp_flags & V4L2_BUF_FLAG_TIMESTAMP_MASK) ==
-				V4L2_BUF_FLAG_TIMESTAMP_COPY)
-			vbuf->timestamp = b->timestamp;
+				V4L2_BUF_FLAG_TIMESTAMP_COPY) {
+			vb->timestamp = timeval_to_ns(&b->timestamp);
+		}

No need to add {} for a one-line statement.


OK, I'll fix it.

  		vbuf->flags |= b->flags & V4L2_BUF_FLAG_TIMECODE;
  		if (b->flags & V4L2_BUF_FLAG_TIMECODE)
  			vbuf->timecode = b->timecode;

<snip>

diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index 647ebfe..6404f81 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -211,6 +211,7 @@ struct vb2_queue;
   * @num_planes:		number of planes in the buffer
   *			on an internal driver queue
   * @planes:		private per-plane information; do not change
+ * @timestamp:		frame timestamp

Please mention the unit (ns).


OK, I'll fix it.

Best regards,
Junghak

   */
  struct vb2_buffer {
  	struct vb2_queue	*vb2_queue;
@@ -219,6 +220,7 @@ struct vb2_buffer {
  	unsigned int		memory;
  	unsigned int		num_planes;
  	struct vb2_plane	planes[VB2_MAX_PLANES];
+	u64			timestamp;

  	/* private: internal use only
  	 *

Other than these minor issues it looks good.

Regards,

	Hans

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