From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
Sequential top-bottom/bottom-top fields are not supported as video loopback.
This is too much work to implement for field settings that are rarely used.
Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
---
Documentation/video4linux/vivid.txt | 5 +++++
drivers/media/platform/vivid/vivid-vid-common.c | 7 +++++++
2 files changed, 12 insertions(+)
diff --git a/Documentation/video4linux/vivid.txt b/Documentation/video4linux/vivid.txt
index 6cfc854..cd4b5a1 100644
--- a/Documentation/video4linux/vivid.txt
+++ b/Documentation/video4linux/vivid.txt
@@ -912,6 +912,11 @@ looped to the video input provided that:
sequence and field counting in struct v4l2_buffer on the capture side may not
be 100% accurate.
+- field settings V4L2_FIELD_SEQ_TB/BT are not supported. While it is possible to
+ implement this, it would mean a lot of work to get this right. Since these
+ field values are rarely used the decision was made not to implement this for
+ now.
+
- on the input side the "Standard Signal Mode" for the S-Video input or the
"DV Timings Signal Mode" for the HDMI input should be configured so that a
valid signal is passed to the video input.
diff --git a/drivers/media/platform/vivid/vivid-vid-common.c b/drivers/media/platform/vivid/vivid-vid-common.c
index 6bef1e6..49c9bc6 100644
--- a/drivers/media/platform/vivid/vivid-vid-common.c
+++ b/drivers/media/platform/vivid/vivid-vid-common.c
@@ -210,6 +210,13 @@ bool vivid_vid_can_loop(struct vivid_dev *dev)
return false;
if (dev->field_cap != dev->field_out)
return false;
+ /*
+ * While this can be supported, it is just too much work
+ * to actually implement.
+ */
+ if (dev->field_cap == V4L2_FIELD_SEQ_TB ||
+ dev->field_cap == V4L2_FIELD_SEQ_BT)
+ return false;
if (vivid_is_svid_cap(dev) && vivid_is_svid_out(dev)) {
if (!(dev->std_cap & V4L2_STD_525_60) !=
!(dev->std_out & V4L2_STD_525_60))
--
2.1.4
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