kernel: uhci_hcd 0000:02:00.4: Controller not stopped yet!
 

HI, I keep seeing the above errors on my server. For this errors I was advised to change the autosuspend value to -1. Right now the value is 2. Can someone please help me understand what the error means and what these values (-1 & 2) are.

Thanks in advance.

# cat autosuspend
2
#echo "-1" > /sys/bus/usb/devices/usb6/power/autosuspend