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When my Logitech C270 webcam is connected, my kernel log gets absolutely polluted with the following message which is generated about every second:
kernel: usb 1-7: reset high-speed USB device number 8 using xhci_hcdI've tried multiple USB ports, both USB 2 and USB 3, but it doesn't seem to make a difference.
The funny thing is, that the webcam seems to work just fine. Even better: when I actually use the webcam, the messages temporarily stop!
FWIW, this is the log when I connect the webcam:
aug 21 14:45:18 Vigil kernel: usb 1-7: new high-speed USB device number 9 using xhci_hcd
aug 21 14:45:18 Vigil kernel: usb 1-7: New USB device found, idVendor=046d, idProduct=0825, bcdDevice= 0.12
aug 21 14:45:18 Vigil kernel: usb 1-7: New USB device strings: Mfr=0, Product=0, SerialNumber=2
aug 21 14:45:18 Vigil kernel: usb 1-7: SerialNumber: B9D9E120
aug 21 14:45:18 Vigil kernel: usb 1-7: Found UVC 1.00 device <unnamed> (046d:0825)
aug 21 14:45:18 Vigil kernel: input: UVC Camera (046d:0825) as /devices/pci0000:00/0000:00:01.3/0000:01:00.0/usb1/1-7/1-7:1.0/input/input40
aug 21 14:45:20 Vigil kernel: usb 1-7: set resolution quirk: cval->res = 384Any ideas?
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I have this same webcam, which if I recall correctly is approaching a double-digit age (I know it's at least 8 years old.) According to this post which was also my initial suspicion, it could be an "electrically marginal" connection. The reason I share this suspicion is because I've happened to use this device over an un-powered USB extension cable in the past, and was told I sounded like a chipmunk! This probably meant that the chipset wasn't receiving sufficient power over USB to power some part of the ADC/DAC circuity; another possible artifact of insufficient power. When I plugged it directly into my PC or a powered USB hub, the problem went away.
In your case, it could stand to reason that the kernel resets go away upon use because the continued communication with the device causes it to pull more current than when idle, thus alleviating it of the "electrically marginal" state mentioned above. My recommendation is to try it with a powered USB hub, and see if this makes any difference. There are also inexpensive Y-cables like this one available, that can allow a USB device to draw power from two separate USB ports, thus theoretically doubling the amount of available current. If for some reason the cabling in your computer is passing less than the standard 5V/0.5A, such a cable could provide similar potential improvements as would a USB hub.
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