This support statement is provided by the Product Management Team.
The aim of this article is to explain our stance on tablet devices that present a touch or pen interface, specifically for DE managed by ePolicy Orchestrator.
Tablets can be divided into two main categories:
- Tablets with a Basic Input/Output System (BIOS) boot process
- Tablets with a Unified Extensible Firmware Interface (UEFI) boot process
NOTES:
- Older style tablet devices like Windows 7 and earlier fall into the BIOS boot group.
- Tablets like Windows 8 and later, generally fall into the second UEFI category.
We have a different support stance for each category as outlined below.
Types of tablet devices
The term
tablet can relate to a few different types of devices. This article covers the following devices when referencing tablets:
- A tablet device that has no physical keyboard and only responds to a touch or pen interface.
This style of device relies on the integrated hardware technology for the touch/pen interface to drive the user interface.
- A hybrid tablet device that has a physically attached keyboard.
Laptop-style devices with a swivel display that hides the keyboard and operate like a tablet, but they can be used as a typical laptop. This style of device can either use the mouse and keyboard, or the integrated hardware technology for the touch/pen interface to drive the user interface.
Symptoms of an incompatible device
The symptoms of an incompatible device in the preboot environment are similar, regardless of whether the device has a BIOS or UEFI boot process. These symptoms can be, but aren't limited to, the list below:
- Device doesn't respond to the touch or pen interface
- Cursor doesn't follow the finger or pen
- Calibration and scaling issues:
- The cursor might move and respond to touch, but not in the same location as was touched. It's offset vertically or horizontally.
- Cursor can be moved off the screen.
Support on devices with a BIOS boot process
For tablet devices with a BIOS boot process, DE provides support for the touch interface hardware for that specific device. The reason is that the preboot environment needs to communicate directly with the hardware. The preboot environment is a proprietary operating system, so device drivers need to be built specifically for different hardware implementations.
Different devices can share underlying hardware, but there are potentially other items such as scaling and calibration that need to be adjusted on each device. As a result, we need to physically develop for, and test, each individual device.
For a list of these devices that are currently supported with DE, see
KB79914 -Wacom USB devices supported with Drive Encryption 7.1.
NOTE: If your device isn't listed, it's highly likely that the touch interface fails to function in the preboot environment.
Support on devices with a UEFI boot process
For tablet devices using UEFI, the OEM needs to provide support for the touch interface hardware for that specific device.
We can claim a more generic support structure based on some minimum conditions for UEFI-based tablet devices. If these minimum conditions are met, the tablet device's touch interface behaves as expected in the preboot environment. Because UEFI is a standard, we depend on the OEMs to provide the required functionality in their UEFI implementation according to the UEFI 2.3.1 specification.
The touch interface works correctly during preboot with DE on tablet devices that satisfy the following minimum conditions:
- Minimum version of UEFI is 2.3.1
- Tablet Device is Windows-hardware certified:
- Device has a Windows hologram
Or
- OEM can verify that their hardware is Windows certified
- One or two UEFI protocols are present and linked to hardware:
- Simple Pointer Protocol:
- Required primarily by a hybrid tablet device to respond to the mouse
- Required by a tablet if a mouse is attached to the USB port (if present)
- Absolute Pointer Protocol:
- Required by both a tablet and hybrid tablet to respond to the touch interface
The Absolute Pointer Protocol, for the touch interface, is the most crucial for support with the preboot environment. If the device doesn't include this protocol, it's likely that the touch interface fails to function in the preboot environment.
The presence of one or both protocols isn't sufficient; the protocol must also be linked to hardware. We can't provide UEFI protocols, or provide a solution if a protocol is missing. Customers must contact their OEM to request a UEFI update/upgrade to include this protocol, or verify the presence of the protocol before purchasing tablet devices.
If the minimum requirements aren't met, it doesn't mean that DE doesn't work on the tablet device. What it means is the following:
- One or more of the defined symptoms above are experienced.
- Users can still authenticate, but they need to attach a keyboard or mouse, which is an undesirable action with a tablet device. With a hybrid tablet device, the keyboard and mouse are already present.
- Apart from not responding to the touch interface in preboot, the product behaves normal.
Testing your UEFI-based device
We've created a simple test tool that customers, partners, and OEMs can use to determine whether their UEFI-based tablet device responds to the touch interface in the preboot environment.
The objective of this UEFI-based Tablet Test Tool is to validate the following:
- The Tablet supports the required UEFI-based protocols
- The OEM correctly implements the UEFI-based protocols
To obtain the tool and for instructions on how to use it, see
KB78050 - How to use the Drive Encryption UEFI testing tool to verify if your tablet responds to the touch interface.
