The complete handling on the control interface is currently dead.
We return with EOPNOTSUPP for the caller to know that a response
to such requests is not valid. The host however may ask
control interface why these control requests were not available.
For this the UVC_VC_REQUEST_ERROR_CODE_CONTROL is used. As an overall
exception for the control interface we just always return 0x06 as
an response which is representing "not implemented".
This patch is a necessary feature to properly pass the UVC Functionality
Test of the USB3CV Compliance Software.
Fixes: 69c17461392d ('uvcgadget: Properly implement GET_INFO control responses')
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/7524>
According to the UVC 1.5 specification, section 4.1.2, the GET_INFO request
must return a bitmap indicating supported operations for the control.
Value 0x00 indicates that neither GET nor SET operations are supported.
This patch fixes control handling in the UVC gadget implementation to properly
respond to GET_INFO requests with the correct bitmap, allowing host systems
to properly detect supported control operations (none in this case).
The pipeline I'm using to test this is:
gst-launch-1.0 videotestsrc ! uvcsink v4l2sink::device=/dev/video0
This is the equivalent of [0] but the difference is that we are now returning
0x00 instead of 0x03.
Without this change the host in my case is unable to probe the UVC gadget at
all, automatically disconnecting the device after a few seconds.
Following is the log when the gadget is not working (without this fix):
usb 1-1.2: new high-speed USB device number 73 using xhci_hcd
usb 1-1.2: New USB device found, idVendor=0525, idProduct=a4a2, bcdDevice= 5.15
usb 1-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 1-1.2: Product: UVC Gadget
usb 1-1.2: Manufacturer: localhost.localdomain
usb 1-1.2: SerialNumber: 0123456789
usb 1-1.2: Found UVC 1.10 device UVC Gadget (0525:a4a2)
usb 1-1.2: Failed to query (GET_INFO) UVC control 2 on unit 1: -110 (exp. 1).
usb 1-1.2: UVC non compliance - GET_DEF(PROBE) not supported. Enabling workaround.
uvcvideo 1-1.2:1.1: Failed to query (129) UVC probe control : -71 (exp. 34).
uvcvideo 1-1.2:1.1: Failed to initialize the device (-71).
cdc_subset 1-1.2:1.0: probe with driver cdc_subset failed with error -22
cdc_subset 1-1.2:1.1: probe with driver cdc_subset failed with error -22
usb 1-1.2: USB disconnect, device number 73
With the fix the USB device is correctly probed:
usb 1-1.2: new high-speed USB device number 88 using xhci_hcd
usb 1-1.2: New USB device found, idVendor=0525, idProduct=a4a2, bcdDevice= 5.15
usb 1-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 1-1.2: Product: UVC Gadget
usb 1-1.2: Manufacturer: localhost.localdomain
usb 1-1.2: SerialNumber: 0123456789
usb 1-1.2: Found UVC 1.10 device UVC Gadget (0525:a4a2)
[0] camera/uvc-gadget@0df9d3ad
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/8572>
This patch adds an element to stream video data to an uvc video gadget.
The element handles the uvc events STREAMON, STREAMOFF, SETUP and DATA.
to start, stop and configure the video buffer flow by the use of pad
probes. It works with linux kernels of versions higher than v6.1.
The element makes use of the v4l2sink proxy property v4l2sink::device
to locate the corresponding device to parse the configfs for additional
data.
The code in uvc.c is basically derived from /lib/uvc.c in
https://git.ideasonboard.org/uvc-gadget.git.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/1304>
