USB Gadget as Camera usb_f_uvc: Invalid argument -22

Hi, 

I was trying to use OrangePi One to add a filter to my USB camera, so that I can apply some image processing to the original input image.

The original project uses raspberrypi: https://github.com/likeablob/rpi-wfh-webcam

It captures the image from a USB Camera, then applys some image processing on Raspberry Pi. Lastly, it creates a virtual camera that sends the output image to the PC.

I would like to achieve the same effect using OrangePi One (Armbian), and the only problem left is to simulate a virtual camera using the USB Gadget.

What I tried:

$ sudo modprobe g_webcam

musb-hdrc.4.auto: failed to start g_webcam: -22

According to this post, a more preferred way to do this is to use configfs:

I followed instructions here: 

https://developer.ridgerun.com/wiki/index.php?title=How_to_use_the_UVC_gadget_driver_in_Linux

But unfortunately, it returned with the same error: Invalid Argument:
 

sudo modprobe libcomposite dwc2 usb_f_uvc

mkdir -p /sys/kernel/config/usb_gadget/g1
cd /sys/kernel/config/usb_gadget/g1
echo 0x0525 > idVendor
echo 0x0102 > idProduct

mkdir -p strings/0x409
echo 0123456789 > strings/0x409/serialnumber
echo $(hostname) > strings/0x409/manufacturer
echo "UVC Gadget" > strings/0x409/product

mkdir configs/c.1
mkdir configs/c.1/strings/0x409

mkdir functions/uvc.0
mkdir -p functions/uvc.0/streaming/uncompressed/u/360p

cat <<EOF > functions/uvc.0/streaming/uncompressed/u/360p/dwFrameInterval
666666
1000000
5000000
EOF

mkdir functions/uvc.0/streaming/header/h
cd functions/uvc.0/streaming/header/h
ln -s ../../uncompressed/u
cd ../../class/fs
ln -s ../../header/h
cd ../../class/hs
ln -s ../../header/h
cd ../../class/ss
ln -s ../../header/h
cd ../../../control
mkdir -p header/h
ln -s header/h class/fs
ln -s header/h class/ss
cd ../../../

echo 2048 > functions/uvc.0/streaming_maxpacket
ln -s functions/uvc.0 configs/c.1

ls /sys/class/udc > UDC

Does this mean the Allwinner H2/H3 USB IP Core does not support g_webcam / usb_f_uvc ?

(Both g_serial and g_eth works, but not g_webcam)

Edited January 27, 20224 yr by wuhanstudio