Peripherals connected through USB-C or Thunderbolt docking stations don't work in the Drive Encryption preboot environment when the system is in legacy BIOS mode

Technical Articles ID: KB91343
Last Modified: 2024-01-06 09:01:10 Etc/GMT

Environment

Drive Encryption (DE) 7.2.0–7.2.8, 7.1.x

Systems with the following:

Legacy BIOS
USB-C or Thunderbolt docking stations

Problem

The DE preboot environment doesn't receive input from peripheral devices, such as a mouse or keyboard, on systems configured in Legacy BIOS mode when connected to either of the following:

USB-C docking station
Thunderbolt docking station

Cause

The DE USB driver only supports USB controllers that are directly connected to the main PCI bus of the system. USB controllers on USB-C or Thunderbolt docking stations don't have the System Management Interrupt line, and instead connect their USB controllers over the PCIe. This design means that the BIOS can't implement transparent USB to PS/2 emulation in System Management Mode, which is what DE Legacy BIOS Preboot requires.

Some BIOS implementations provide emulation using standard interrupts, but the handlers for these implementations only operate in 16-bit real mode. DE Legacy BIOS preboot uses the 32-bit protected mode, and thus can't use the 16-bit real mode handlers.

We're not planning to overhaul DE Legacy BIOS to support PCIe or PCI-to-PCI bridging, and because Legacy BIOS is being deprecated in favor of UEFI firmware, it's not being considered currently.

Solution 1

This issue is resolved with DE 7.2.9.

Issue resolutions in updates and major releases are cumulative; Technical Support recommends that you install the latest version. To find the most recent release for your product, go to the Product Downloads site.

Our product software, upgrades, maintenance releases, and documentation are available on the Product Downloads site.

NOTE: You need a valid Grant Number for access. See KB56057 - How to download product updates and documentation for more information about the Product Downloads site, and alternate locations for some products.

Solution 2

Customers are encouraged to migrate away from Legacy BIOS when activating DE on new systems, and instead activate DE in UEFI mode in the future.

UEFI firmware mode provides better support for peripherals connected through USB-C and Thunderbolt docking stations.

UEFI also provides an easier reference for dialog with manufacturers to request the addition of peripheral support, if it doesn't exist in the vendor's firmware.

Knowledge Center

Peripherals connected through USB-C or Thunderbolt docking stations don't work in the Drive Encryption preboot environment when the system is in legacy BIOS mode

Environment

Problem

Cause

Solution 1

Solution 2

Workaround

Affected Products

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Knowledge Center

Peripherals connected through USB-C or Thunderbolt docking stations don't work in the Drive Encryption preboot environment when the system is in legacy BIOS mode

Environment

Problem

Cause

Solution 1

Solution 2

Workaround

Affected Products

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