[PATCH v5 09/13] media: uvcvideo: Increase the size of UVC_METADATA_BUF_SIZE

From: Ricardo Ribalda
Date: Tue Mar 16 2021 - 14:03:47 EST


Hans has discovered that in his test device, for the H264 format
bytesused goes up to about 570, for YUYV it will actually go up
to a bit over 5000 bytes, and for MJPG up to about 2706 bytes.

We should also, according to V4L2_META_FMT_UVC docs, drop headers when
the buffer is full.

Credit-to: Hans Verkuil <hverkuil@xxxxxxxxx>
Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
---
drivers/media/usb/uvc/uvc_video.c | 8 +++++---
drivers/media/usb/uvc/uvcvideo.h | 2 +-
2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
index 25fd8aa23529..ea2903dc3252 100644
--- a/drivers/media/usb/uvc/uvc_video.c
+++ b/drivers/media/usb/uvc/uvc_video.c
@@ -1244,11 +1244,13 @@ static void uvc_video_decode_meta(struct uvc_streaming *stream,
if (!meta_buf || length == 2)
return;

+ /*
+ * According to V4L2_META_FMT_UVC docs, we should drop headers when
+ * the buffer is full.
+ */
if (meta_buf->length - meta_buf->bytesused <
- length + sizeof(meta->ns) + sizeof(meta->sof)) {
- meta_buf->error = 1;
+ length + sizeof(meta->ns) + sizeof(meta->sof))
return;
- }

has_pts = mem[1] & UVC_STREAM_PTS;
has_scr = mem[1] & UVC_STREAM_SCR;
diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index b81d3f65e52e..a26bbec8d37b 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h
@@ -527,7 +527,7 @@ struct uvc_stats_stream {
unsigned int max_sof; /* Maximum STC.SOF value */
};

-#define UVC_METADATA_BUF_SIZE 1024
+#define UVC_METADATA_BUF_SIZE 10240

/**
* struct uvc_copy_op: Context structure to schedule asynchronous memcpy
--
2.31.0.rc2.261.g7f71774620-goog