Ubuntu 19.10 / 20.04 webcam crashing

This is a follow up of this question: Merlin U740 USB 2.0 camera not working

Basically I have Merlin U740 USB 2.0 camera. I managed to make it work on Ubuntu 18.04 and it was working well until I upgraded to 19.10. A subsequent upgrade to 20.04 didn't make any difference and now the camera doesn't work.

It's recognised by the system and starts in Zoom, Slack and Cheese only to fail a few seconds later, causing Zoom to freeze / become unresponsive for a moment (up to 30s, other apps seem to handle it better). I tried all the USB ports available on my PC and it made no difference.

I ran the usual commands and here are the results:

lsmod | grep video

uvcvideo               98304  0
videobuf2_vmalloc      20480  1 uvcvideo
videobuf2_memops       20480  1 videobuf2_vmalloc
videobuf2_v4l2         24576  1 uvcvideo
videobuf2_common       49152  2 videobuf2_v4l2,uvcvideo
videodev              225280  3 videobuf2_v4l2,uvcvideo,videobuf2_common
mc                     53248  5 videodev,snd_usb_audio,videobuf2_v4l2,uvcvideo,videobuf2_common

lsusb

Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 010: ID 1410:1410 Novatel Wireless Merlin U740 (non-Vodafone)
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 003: ID 1ea7:0064 SHARKOON Technologies GmbH 2.4G Mouse
Bus 001 Device 002: ID 046d:c534 Logitech, Inc. Unifying Receiver
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

dmesg -H

[May26 08:07] usb 3-4: USB disconnect, device number 2
[  +0.001971] uvcvideo: Failed to resubmit video URB (-19).
[  +0.003994] uvcvideo: Failed to resubmit video URB (-19).
[  +0.004001] uvcvideo: Failed to resubmit video URB (-19).
[  +0.003998] uvcvideo: Failed to resubmit video URB (-19).
[  +0.004001] uvcvideo: Failed to resubmit video URB (-19).
[  +0.334387] usb 3-4: new high-speed USB device number 9 using xhci_hcd
[  +0.113622] usb 3-4: New USB device found, idVendor=1410, idProduct=1410, bcdDevice= 0.00
[  +0.000003] usb 3-4: New USB device strings: Mfr=2, Product=1, SerialNumber=0
[  +0.000001] usb 3-4: Product: USB 2.0 Camera
[  +0.000001] usb 3-4: Manufacturer: Sonix Technology Co., Ltd.
[  +0.010509] uvcvideo: Found UVC 1.00 device USB 2.0 Camera (1410:1410)
[  +0.025696] uvcvideo 3-4:1.0: Entity type for entity Extension 4 was not initialized!
[  +0.000002] uvcvideo 3-4:1.0: Entity type for entity Processing 3 was not initialized!
[  +0.000001] uvcvideo 3-4:1.0: Entity type for entity Camera 1 was not initialized!
[  +0.000059] input: USB 2.0 Camera: SD webcam 5160 as /devices/pci0000:00/0000:00:08.1/0000:09:00.3/usb3/3-4/3-4:1.0/input/input31
[  +0.013231] usb 3-4: 3:1: cannot get freq at ep 0x84
[  +0.022373] usb 3-4: USB disconnect, device number 9
[  +0.342659] usb 3-4: new high-speed USB device number 10 using xhci_hcd
[  +0.118345] usb 3-4: New USB device found, idVendor=1410, idProduct=1410, bcdDevice= 0.00
[  +0.000002] usb 3-4: New USB device strings: Mfr=2, Product=1, SerialNumber=0
[  +0.000001] usb 3-4: Product: USB 2.0 Camera
[  +0.000002] usb 3-4: Manufacturer: Sonix Technology Co., Ltd.
[  +0.009629] uvcvideo: Found UVC 1.00 device USB 2.0 Camera (1410:1410)
[  +0.025813] uvcvideo 3-4:1.0: Entity type for entity Extension 4 was not initialized!
[  +0.000002] uvcvideo 3-4:1.0: Entity type for entity Processing 3 was not initialized!
[  +0.000001] uvcvideo 3-4:1.0: Entity type for entity Camera 1 was not initialized!
[  +0.000058] input: USB 2.0 Camera: SD webcam 5160 as /devices/pci0000:00/0000:00:08.1/0000:09:00.3/usb3/3-4/3-4:1.0/input/input32
[  +0.013238] usb 3-4: 3:1: cannot get freq at ep 0x84
[  +0.203878] usb 3-4: 3:1: cannot get freq at ep 0x84
[  +0.012130] usb 3-4: 3:1: cannot get freq at ep 0x84

The camera doesn't seem damaged in any way, but maybe there's something wrong with the hardware itself?

I have Ubuntu 19.10 and faced this issue several days ago too. The reason is updating from 5.3.0-53 kernel to 5.3.0-55. As a workaround, you can choose 53 version in GRUB. For 20.04 kernel version 5.6.15 should work: Webcam stopped working after recent kernel update