My “Hercules Dualpix Chat and Show” Webcam (06f8:3007) is on the list of UVC supported devices (http://www.ideasonboard.org/uvc/). Yeay! Alas, uvcvideo fails to “initialize the device”, about 80% of the time. I have to unplug and plug it again until it works, sometimes failing many times in a row, sometimes with a reboot required. I am unable to determine what makes it fail. Perhaps a relevant error given by uvcvideo is: “Failed to query (129) UVC probe control : -32 (exp. 26)”, in case it rings a bell. (This case reports an identical error: https://sourceforge.net/p/linux-uvc/mailman/message/34454922/, and this case reports similar symptoms: https://www.spinics.net/lists/linux-media/msg05303.html, both with a different device.) Here is the relevant part of dmesg, when it fails. (I tried with “all uvcvideo module traces enabled”, as per the troubleshooting instructions, but it does not seem to bring supplementary relevant data.) [ 8204.297059] (-> XU 6) [ 8204.297061] uvcvideo: Found a valid video chain (1 -> 3). [ 8204.297417] uvcvideo: UVC non compliance - GET_DEF(PROBE) not supported. Enabling workaround. [ 8204.297793] uvcvideo: Failed to query (129) UVC probe control : -32 (exp. 26). [ 8204.297799] uvcvideo: Failed to initialize the device (-5). [ 8204.300037] usb 2-3: 3:1: cannot get freq at ep 0x84 [ 8204.381954] usb 2-3: 3:1: cannot get freq at ep 0x84 [ 8204.419980] usb 2-3: 3:1: cannot get freq at ep 0x84 [ 8209.435819] retire_capture_urb: 5003 callbacks suppressed [ 8233.273816] usb 2-3: USB disconnect, device number 7 After this, my linux system, debian stable, fails (expectedly) to recognise the camera, with two browsers (Firefox and Chromium). Here is the relevant part of dmesg, when it succeeds. [ 8114.578523] (-> XU 6) [ 8114.578525] uvcvideo: Found a valid video chain (1 -> 3). [ 8114.578769] uvcvideo: UVC non compliance - GET_DEF(PROBE) not supported. Enabling workaround. [ 8114.579687] uvcvideo 2-3:1.0: Entity type for entity Processing 5 was not initialized! [ 8114.579688] uvcvideo 2-3:1.0: Entity type for entity Selector 4 was not initialized! [ 8114.579690] uvcvideo 2-3:1.0: Entity type for entity Camera 1 was not initialized! [ 8114.579691] uvcvideo 2-3:1.0: Entity type for entity Guillemot Corporation was not initialized! [ 8114.579822] input: Hercules Dualpix Chat and Show as /devices/pci0000:00/0000:00:13.2/usb2/2-3/2-3:1.0/input/input19 [ 8114.579960] uvcvideo: UVC device initialized. [ 8114.581789] usb 2-3: 3:1: cannot get freq at ep 0x84 [ 8114.630633] uvcvideo: uvc_v4l2_open [ 8114.630712] uvcvideo: uvc_v4l2_release [ 8114.683510] usb 2-3: 3:1: cannot get freq at ep 0x84 [ 8114.714065] usb 2-3: 3:1: cannot get freq at ep 0x84 [ 8119.878947] retire_capture_urb: 4996 callbacks suppressed [ 8122.507661] uvcvideo: Suspending interface 1 [ 8122.507664] uvcvideo: Suspending interface 0 [ 8192.245098] usb 2-3: USB disconnect, device number 6 After this, the browsers do recognize the webcam (e.g. https://webrtc.github.io/test-pages/src/audio-and-video/). Is hope permitted? Or should I just buy another webcam? Any idea is appreciated. -- Olivier
