Symptoms
When restarting Windows or when inserting/unplugging a USB 2.0 device to an Enhanced Host Controller where there are other USB 2.0 devices attached, you may encounter the following symptoms:
- Some USB ports are disabled and as a result, USB 2.0 devices attached to these ports appear with a Yellow Exclamation in device manager.
Cause
You have attached one or more USB 2.0 non-compliant devices that are not certified for Windows Vista and later operating systems. These devices can cause this condition.
Resolution
In order to prevent and recover from these symptoms, it is recommended to remove non-compliant USB 2.0 devices such as USB flash drives from the system.
More Information
These USB devices were likely produced prior to the release of Windows Vista and Windows 7. Therefore are not certified for these operating systems, and are non-compliant to the USB 2.0 specification. These devices may not work correctly with some AMD systems with built in EHCI Host Controllers.
Flash devices known to cause this condition with AMD systems but could also affect other systems are:
Technical details:
USB 2.0 non-compliant devices connected to a EHCI Host port can generate what is termed as a "babble condition" (where the device continues to talk outside of its frame). As a result, the host controller detects the Babble condition and disables the offending port. However, if the Babble condition happens at the end of the Frame, due to a Host Controller logic issue on some AMD systems, the Host Controller also disables all other downstream ports within this controller.
Example: In AMD Hudson 1 based systems there are 5 (five) ports per EHCI controller. If a Babble condition is detected on port 3, then all five ports, port 0 to 4, are disabled by the Host controller.
Flash devices known to cause this condition with AMD systems but could also affect other systems are:
- Toshiba Model # U2M-016GT
- Kingston Model DT 4G
Technical details:
USB 2.0 non-compliant devices connected to a EHCI Host port can generate what is termed as a "babble condition" (where the device continues to talk outside of its frame). As a result, the host controller detects the Babble condition and disables the offending port. However, if the Babble condition happens at the end of the Frame, due to a Host Controller logic issue on some AMD systems, the Host Controller also disables all other downstream ports within this controller.
Example: In AMD Hudson 1 based systems there are 5 (five) ports per EHCI controller. If a Babble condition is detected on port 3, then all five ports, port 0 to 4, are disabled by the Host controller.