AN75779无法查询UVC控件

我正试图建立一个基于AN7799的系统来工作。我在Linux下运行（内核4.12.5）。
当我奔跑
V4L2GAP-MQ 100 D/DEV/VIDO0/O/TMP/GAPP.JPG
当运行V4L2GRAP时，得到以下输出
通过设备/DEV/VIDO0将图像宽度设置为1280。
图像高度由设备/DEV/VIDO0设置为720。
然后它就挂了。
在我的FX3控制台上，我观察到当启动V4L2GRAPH时激活了流
UVC：完成0帧和0缓冲器
UVC：完成0帧和0缓冲器
UVC：完成0帧和0缓冲器
UVC：完成21帧和3缓冲器
UVC：完成42帧和19缓冲器
UVC：完成63帧和35缓冲器
UVC：完成84帧和51缓冲器
UVC：完成106帧和9缓冲器
然而，在Linux主机内核日志中，我观察到：
[7446.534814 ] UVCVID:找到UVC 1设备FX3（04B4:00 F9）
[7446.536477 ] UVCVIEW 2-6:1.0：实体扩展3的实体类型未初始化！
[ 7446.536482 ] uvcvideo 2-6:1.0：实体处理2个实体类型没有被初始化！
[ 7446.536485 ] uvcvideo 2-6:1.0：实体相机1实体类型没有被初始化！
【7446.536654】输入：FX3 /设备/ pci0000:00 / 0000:00:14.0 / USB2 / 2-6 / 2-6: 1.0/input/input13
[ 8488.136849 ] uvcvideo：无法查询（get_def）UVC控制2单元2：1（预期值2）。
什么是错误“无法查询（get_def）引起的UVC控制”？
V4L2Grand工作良好，如果插入一个普通的USB网络摄像头。



     以下为原文
  I'm trying to get a system based upon AN75779 to work. I'm running under Linux (kernel 4.12.5).

When I run

v4l2grab -m -q 100 -d /dev/video0 -o /tmp/grab.jpg


When I run v4l2grab I get the following output
Image width set to 1280 by device /dev/video0.
Image height set to 720 by device /dev/video0.
and then it just hangs.


On my FX3 console I observe that streaming is activated when I start v4l2grab

UVC: Completed 0 frames and 0 buffers
UVC: Completed 0 frames and 0 buffers
UVC: Completed 0 frames and 0 buffers
UVC: Completed 21 frames and 3 buffers
UVC: Completed 42 frames and 19 buffers
UVC: Completed 63 frames and 35 buffers
UVC: Completed 84 frames and 51 buffers
UVC: Completed 106 frames and 9 buffers


However, in the Linux host kernel log I observe:

[ 7446.534814] uvcvideo: Found UVC 1.00 device FX3 (04b4:00f9)
[ 7446.536477] uvcvideo 2-6:1.0: Entity type for entity Extension 3 was not initialized!
[ 7446.536482] uvcvideo 2-6:1.0: Entity type for entity Processing 2 was not initialized!
[ 7446.536485] uvcvideo 2-6:1.0: Entity type for entity Camera 1 was not initialized!
[ 7446.536654] input: FX3 as /devices/pci0000:00/0000:00:14.0/u***2/2-6/2-6:1.0/input/input13
[ 8488.136849] uvcvideo: Failed to query (GET_DEF) UVC control 2 on unit 2: 1 (exp. 2).


What is the error "Failed to query (GET_DEF) UVC control" caused by?


v4l2grab works fine if plug in a plain USB web camera.