Very old thread, but this is still very applicable. I have some devices that would not connect and this fixed it.
Originally Posted by toni_uk
The old value was 2 (seconds).
Here is some documentation for some of the other values that can be configured:
[USB] The autosuspend time delay (in seconds) used
for newly-detected USB devices (default 2). This
is the time required before an idle device will be
autosuspended. Devices for which the delay is set
to a negative value won't be autosuspended at all.
[USB] Set to log all usbfs traffic (default 0 = off).
[USB] Set to cycle leds on hubs (default 0 = off).
[USB] Start with the old device initialization
scheme (default 0 = off).
[USB] Try the other device initialization scheme
if the first one fails (default 1 = enabled).
[USB] Specifies timeout for the initial 64-byte
USB_REQ_GET_DESCRIPTOR request in milliseconds
(default 5000 = 5.0 seconds).