Some cameras, such as the Sonix Technology Co. 292A, exhibit issues when
running two parallel streams, causing USB packets to be dropped when an
H.264 stream posts a keyframe while an MJPEG stream is running
simultaneously. This occasionally causes the driver to erroneously
output two consecutive JPEG images as a single frame.
To fix this, we inspect the buffer, and trigger a new frame when we
find an SOI.
Signed-off-by: Isaac Scott <isaac.scott@xxxxxxxxxxxxxxxx>
---
drivers/media/usb/uvc/uvc_video.c | 27 ++++++++++++++++++++++++++-
drivers/media/usb/uvc/uvcvideo.h | 1 +
2 files changed, 27 insertions(+), 1 deletion(-)
diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
index e00f38dd07d9..6d800a099749 100644
--- a/drivers/media/usb/uvc/uvc_video.c
+++ b/drivers/media/usb/uvc/uvc_video.c
@@ -20,6 +20,7 @@
#include <linux/atomic.h>
#include <linux/unaligned.h>
+#include <media/jpeg.h>
#include <media/v4l2-common.h>
#include "uvcvideo.h"
@@ -1116,6 +1117,7 @@ static void uvc_video_stats_stop(struct uvc_streaming *stream)
static int uvc_video_decode_start(struct uvc_streaming *stream,
struct uvc_buffer *buf, const u8 *data, int len)
{
+ u8 header_len;
u8 fid;
/*
@@ -1129,6 +1131,7 @@ static int uvc_video_decode_start(struct uvc_streaming *stream,
return -EINVAL;
}
+ header_len = data[0];
fid = data[1] & UVC_STREAM_FID;
/*
@@ -1210,9 +1213,31 @@ static int uvc_video_decode_start(struct uvc_streaming *stream,
return -EAGAIN;
}
+ /*
+ * Some cameras, when running two parallel streams (one MJPEG alongside
+ * another non-MJPEG stream), are known to lose the EOF packet for a frame.
+ * We can detect the end of a frame by checking for a new SOI marker, as
+ * the SOI always lies on the packet boundary between two frames for
+ * these devices.
+ */
+ if (stream->dev->quirks & UVC_QUIRK_MJPEG_NO_EOF &&
+ (stream->cur_format->fcc == V4L2_PIX_FMT_MJPEG ||
+ stream->cur_format->fcc == V4L2_PIX_FMT_JPEG)) {
+ const u8 *packet = data + header_len;
+
+ if (len >= header_len + 2 &&
+ packet[0] == 0xff && packet[1] == JPEG_MARKER_SOI &&
+ buf->bytesused != 0) {
+ buf->state = UVC_BUF_STATE_READY;
+ buf->error = 1;
+ stream->last_fid ^= UVC_STREAM_FID;
+ return -EAGAIN;
+ }
+ }
+
stream->last_fid = fid;
- return data[0];
+ return header_len;
}
static inline enum dma_data_direction uvc_stream_dir(
diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index b7d24a853ce4..040073326a24 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h
@@ -76,6 +76,7 @@
#define UVC_QUIRK_NO_RESET_RESUME 0x00004000
#define UVC_QUIRK_DISABLE_AUTOSUSPEND 0x00008000
#define UVC_QUIRK_INVALID_DEVICE_SOF 0x00010000
+#define UVC_QUIRK_MJPEG_NO_EOF 0x00020000
/* Format flags */
#define UVC_FMT_FLAG_COMPRESSED 0x00000001
--
2.43.0
