We have this issue when plugging in a USB Camera.In Ubuntu 12.04 it takes less than 10s for the device to be available, while in 14.04 and 16.04 it takes at least 40s. We have monitored it using udevadm monitor and as you can see in 12.04 it goes from 21650 to 21660, while in 16.04 it goes from 730 to 780. We haven't found any discussions regarding this issue in the internet.Does anybody know exactly what is happening during that time? Is there some kind of timeout? We couldn't detect any activity going on..Thanks for helping!UDEV Version 175 / Ubuntu 12.04.4 LTS / 3.8.0-42-genericudevadm monitor output:monitor will print the received events for:UDEV - the event which udev sends out after rule processingKERNEL - the kernel ueventKERNEL[21650.208878] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1 (usb)KERNEL[21650.209686] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.0 (usb)KERNEL[21650.211448] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.0/video4linux/video0 (video4linux)KERNEL[21650.211513] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.0/input/input9 (input)KERNEL[21650.211595] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.0/input/input9/event8 (input)KERNEL[21650.211671] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.1 (usb)KERNEL[21650.211716] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.2 (usb)KERNEL[21660.213820] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.2/sound/card2 (sound)KERNEL[21660.214003] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.2/sound/card2/pcmC2D0c (sound)KERNEL[21660.214138] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.2/sound/card2/controlC2 (sound)KERNEL[21660.214201] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.3 (usb)UDEV  [21660.231373] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1 (usb)UDEV  [21660.233076] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.1 (usb)UDEV  [21660.234140] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.0 (usb)UDEV  [21660.234183] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.3 (usb)UDEV  [21660.234213] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.2 (usb)UDEV  [21660.235493] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.2/sound/card2 (sound)KERNEL[21660.237599] change   /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.2/sound/card2 (sound)UDEV  [21660.239128] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.2/sound/card2/pcmC2D0c (sound)UDEV  [21660.240370] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.0/input/input9 (input)UDEV  [21660.243607] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.0/input/input9/event8 (input)UDEV  [21660.260399] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.2/sound/card2/controlC2 (sound)UDEV  [21660.263147] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.0/video4linux/video0 (video4linux)UDEV  [21660.273712] change   /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.2/sound/card2 (sound)UDEV Version 229 / Ubuntu 16.04.1 LTS / 4.4.0-47-genericudevadm monitor output:monitor will print the received events for:UDEV - the event which udev sends out after rule processingKERNEL - the kernel ueventKERNEL[730.408258] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1 (usb)KERNEL[730.409317] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.0 (usb)KERNEL[730.409488] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.0/media0 (media)KERNEL[730.411130] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.0/video4linux/video0 (video4linux)KERNEL[730.411209] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.0/input/input17 (input)KERNEL[730.411369] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.0/input/input17/event12 (input)KERNEL[730.411453] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.1 (usb)KERNEL[730.411503] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.2 (usb)KERNEL[780.413898] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.2/sound/card1 (sound)KERNEL[780.414403] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.2/sound/card1/controlC1 (sound)KERNEL[780.414678] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.2/sound/card1/pcmC1D0c (sound)KERNEL[780.414858] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.3 (usb)UDEV  [780.432584] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1 (usb)UDEV  [780.433911] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.0 (usb)UDEV  [780.442149] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.1 (usb)UDEV  [780.442209] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.0/media0 (media)UDEV  [780.442337] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.0/input/input17 (input)UDEV  [780.442418] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.2 (usb)UDEV  [780.442485] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.3 (usb)UDEV  [780.442533] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.2/sound/card1 (sound)KERNEL[780.444785] change   /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.2/sound/card1 (sound)UDEV  [780.452855] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.0/video4linux/video0 (video4linux)UDEV  [780.456923] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.2/sound/card1/pcmC1D0c (sound)UDEV  [780.461042] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.2/sound/card1/controlC1 (sound)UDEV  [780.463634] change   /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.2/sound/card1 (sound)UDEV  [780.497977] add      /devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1:1.0/input/input17/event12 (input)
udevadmin monitor 1 minute delay when plugging in usb camera
ubuntu;kernel;usb;udev