[linux-uvc-devel] UVC driver and USB gadget driver

[Giri Babu]

Hello everybody,
I am trying to understand Linux UVC drivers and the gadget drivers. Towards
it, I started testing webcam gadget (*g_webcam*) driver with the help of
Linux UVC driver "*uvcvideo*". My Host and device kernels are 3.2.0-56 and
3.2.1 respectively. Host side "dmesg" command gives me the following error
after Mr laurent's* uvc-gadget* application is executed inside the device.

usb 2-1.7: new high-speed USB device number 10 using ehci_hcd
uvcvideo: Found UVC 1.00 device Webcam gadget (1d6b:0102)
uvcvideo: Failed to query (129) UVC probe control : -71 (exp. 26).
uvcvideo: Failed to initialize the device (-5).
usb 2-1.7: USB disconnect, device number 10


Then i tried executing the below commands on the host
sudo rmmod uvcvideo
sudo modprobe uvcvideo quirks=0x100

Still the webcam gadget is not initialized properly and dmesg output shows
usbcore: deregistering interface driver uvcvideo
usbcore: registered new interface driver uvcvideo
USB Video Class driver (1.1.1)
usb 2-1.7: new high-speed USB device number 11 using ehci_hcd
uvcvideo: Found UVC 1.00 device Webcam gadget (1d6b:0102)
uvcvideo: Forcing device quirks to 0x100 by module parameter for
testing purpose.
uvcvideo: Please report required quirks to the linux-uvc-devel
mailing list.
uvcvideo: Failed to query (129) UVC probe control : -71 (exp. 26).
uvcvideo: Failed to initialize the device (-5).
usb 2-1.7: USB disconnect, device number 11


Can anyone please help me to find the exact problem why the gadget is
failing to initialize. I could not even locate the issue where it is. Is
there any issue with gadget driver or with uvcvideo?

Thanks in advance


Best regards
-------------------
Giri