- You have an Intel® Atom™ Processor Z373x series based or Intel Cherry Trail Cost Reduction (CHT-CR)-based computer that is running Windows 8.1.
- The computer has an external USB 2.0 port.
- You try to perform kernel debugging on the device by plugging a USB 3.0 cable into the USB 2.0 port.
Note After you apply this update, you can perform kernel debugging on Intel® Atom™ Processor Z373x and CHT-CR devices by plugging a USB 3.0 cable into the external USB 2.0 port. This feature is also supported on full Intel® Atom™ Processor Z374x, Z377x, Z378x, Z379x or N28xx/N29xx and CHT devices when plugging a USB 2.0 cable into the external USB 3.0 port, because the external USB 3.0 port is backward-compatible with USB 2.0.
Method 1: Windows UpdateThis update is available from Windows Update.
Method 2: Update RollupTo resolve this issue, install the November 2014 update rollup for Windows RT 8.1, Windows 8.1, or Windows Server 2012 R2.
Prerequisites for hardware settingsTo apply this update, you have to meet the following conditions:
- The firmware should have the Extensible Device Controller Interface (xDCI) Debug Port Table 2 (DBG2) entry.
- The xDCI controller is exposed correctly to the desired USB debug port.
- The OEM firmware has to hide the xDCI controller in PCI, or expose it as an ACPI device instead of as a PCI device.
Note The base address for xDCI will be pointed to by the DBG2 table entry.
- The USB cable should be plugged in before the platform starts.
See DBG2 spec to check for more information.
The following table contains the important fields for the xDCI DBG2 table entry:
|Register_Bit_Width||32 bits (0x20)|
|BaseAddressRegister||<Dynamically Assign based on xDCI PCI BAR0>|
|Port Type||USB (0x8002)|
|Port Subtype||Synopsys xDCI (0x0007)|
Article ID: 3003727 - Last Review: Jan 21, 2015 - Revision: 1