Hello Laurent
>> May 28 10:53:26 lapsystemx kernel: uvcvideo: uvc_v4l2_ioctl(VIDIOC_STREAMON)
>> May 28 10:53:26 lapsystemx kernel: uvcvideo: uvc_v4l2_ioctl(VIDIOC_DQBUF)
>> May 28 10:53:28 lapsystemx kernel: uvcvideo: Frame complete (overflow).
>> May 28 10:53:28 lapsystemx kernel: uvcvideo: Dropping payload (out of sync).
>> May 28 10:53:28 lapsystemx last message repeated 18 times
>> May 28 10:53:28 lapsystemx kernel: uvcvideo: Dequeuing buffer 0 (3, 307789
>> bytes).
>> May 28 10:53:28 lapsystemx kernel: uvcvideo: uvc_v4l2_ioctl(VIDIOC_QBUF)
>> May 28 10:53:28 lapsystemx kernel: uvcvideo: Queuing buffer 0.
>> May 28 10:53:28 lapsystemx kernel: uvcvideo: uvc_v4l2_ioctl(VIDIOC_DQBUF)
>> May 28 10:53:28 lapsystemx kernel: uvcvideo: Dropping payload (out of sync).
>> May 28 10:53:59 lapsystemx last message repeated 30784 times
>> May 28 10:55:00 lapsystemx last message repeated 60992 times
>> MESSAGE cntrl backslash
>> May 28 10:55:24 lapsystemx last message repeated 24351 times
>> May 28 10:55:24 lapsystemx kernel: uvcvideo: uvc_v4l2_release
>> MESSAGE done
>
> It seems the device doesn't toggle the FID bit in the UVC
> packet header. Could you try loading the driver with
> quirks=16 ?
First of all it sure looks light the camera
is indeed streaming since I get the line
uvcvideo: Dequeuing buffer 0 (3, 307789 bytes)
which is very close to the format
640x480=307200 + 589 control bytes (whatever they are)
Okay I tried the following command (and a million other variations)
modprobe -v uvcvideo trace=255 quirks=16
and got the line from the kernel log
kernel: uvcvideo: Forcing device quirks 0x10
by module parameter for testing purpose.
This has no effect at all, same output as the trace above,
so I thought it might be a good idea to see what was
happening in the header. Now if I went to the wrong place
then all my data is wrong.
I went to the call
"static int uvc_video_decode_start"
in the file "uvc_video.c"
I added the lines
__u8 packet_header;
packet_header=data[1] & 255;
uvc_trace(UVC_TRACE_FRAME, "packet header=%d\n",
packet_header);
After compiling, installing and reloading
I immediately got many pages of
packet header=141
so I tried the following, see if the header ever changes.
if (packet_header != 141)
uvc_trace(UVC_TRACE_FRAME, "packet header=%d\n",
packet_header);
which never got printed. In other words the packet header is
always 141 and we have the information below
UVC_STREAM_EOH (1 << 7) 1 (set)
UVC_STREAM_ERR (1 << 6) 0 (reset)
UVC_STREAM_STI (1 << 5) 0 (reset)
UVC_STREAM_RES (1 << 4) 0 (reset)
UVC_STREAM_SCR (1 << 3) 1 (set)
UVC_STREAM_PTS (1 << 2) 1 (set)
UVC_STREAM_EOF (1 << 1) 0 (reset)
UVC_STREAM_FID (1 << 0) 1 (set)
Looking forward to your comments
regards bruce
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