ClearCube R1200 Technical Document

Topic:
Component(s) Affected:
Date:
TB0062.fm — Incorrect USB Power Settings Cause C/Ports to Lose Connectivity

OVERVIEW / ENVIRONMENT

Incorrect USB Power Management settings can cause C/Ports connected to R1200 and R2100 Blades to
become unresponsive to any input at the C/Port.

DETAILED DESCRIPTION

This Tech Bulletin addresses a number of symptoms with interrelated causes and effects. The most com-
mon symptom is that C/Ports lose connectivity in unpredictable ways, connectivity cannot be restored at
the C/Port, and troubleshooting the problems isn't always successful or repeatable.
In almost all cases, these problem are symptomatic of improper USB Power Management settings in the
System Control Panel. The actual causes run deeper.

Quick-Fix Resolution:

1. Reboot the Blade locally (at the Blade).
2. From the System Control Panel, disable Power Management for all USB Root Hubs listed. Uncheck the
"Allow the computer to turn off this device" box for all USB Root Hubs listed. See Figure 1.
3. Reboot the Blade again.
The user should regain control at the C/Port, at least temporarily — until the next hardware reconfiguration
or C/Port cable hot-swap.
Note: This may not resolve the underlying causes of the problem. It only gets the user back online.
Figure 1 Device Manager Window, Hardware Tab, Viewed by Type
ClearCube Technology 8834 Capital of Texas Hwy N Suite 140 Austin, Texas 78759 voice 512 652 3500 www.clearcube.com
Incorrect USB Power Settings Cause C/Ports to Lose Connectivity
R1200 Blades, C/Ports, Disk Images
November 12, 2004
ClearCube Public Technical Document
Document Code: SE0062JS
TB0062 rev 11/12/2004