UVC Gadget Bind Failure on imx-6.6.23-2.0.0.xml

[yslee_]

Hi all,

I'm currently testing a composite USB gadget setup (UVC) on an i.MX8MP platform using configfs and a shell script (test.sh). The setup works perfectly on the following NXP BSP branches:

SUCCESS : imx-5.4.70-2.3.0.xml (Yocto zeus) — /dev/video1 is created

SUCCESS : imx-5.15.71-2.2.0.xml (Yocto kirkstone) — /dev/video1 is created

However, on:

FAIL : imx-6.6.23-2.0.0.xml (Yocto scarthgap)

the script fails with the following log:

[test-usb-composite] Creating USB gadget: test

[test-usb-composite] Setting device descriptors...

[test-usb-composite] Setting string descriptors...

[test-usb-composite] Creating configuration...

[test-usb-composite] Creating UVC gadget functionality : uvc.usb0

[test-usb-composite] Binding gadget to UDC: 38100000.usb

configfs-gadget.test gadget.0: uvc: uvc_function_bind()

udc 38100000.usb: failed to start test: -19

UDC core: test: couldn't find an available UDC or it's busy

./test.sh: line 203: echo: write error: Device or resource busy

Build info:

Image: imx-image-core

Platform: 

i.MX8MP EVK

Kernel config (relevant options enabled):

CONFIG_USB_FUNCTIONFS=m

CONFIG_GADGET_UAC1=y

CONFIG_GADGET_UAC1_LEGACY=y

CONFIG_USB_G_WEBCAM=m

CONFIG_USB_G_HID=m

CONFIG_USB_VIDEO_CLASS=y

Observations:

No /dev/video1 appears.

Script and function registration steps are identical across all tests.

Only this BSP (6.6.23) exhibits the binding failure.

Questions:

Has anyone encountered this with the 6.6.23 BSP?

Is there a missing dependency or patch for uvc_function_bind() in this version?

Is this a known regression, or does UVC gadget support require additional configuration in this kernel?

Any suggestions or solutions would be greatly appreciated.

Thanks,

[Zhiming_Liu · Accepted solution]

Hi 

This script can work.

Best Regards,
Zhiming