BIOS Communication for Display Drivers in Windows Vista
Guidelines for how to implement ACPI support and related support in WDDM display drivers to support communication between the system BIOS and graphics hardware on a system running Windows Vista. For driver developers, BIOS vendors, and system manufacturers.
File name: wddm_bios.doc
Microsoft Word file
Display drivers often communicate with the system BIOS to provide advanced functionality that might depend on machine-specific or OEM-specific system BIOS implementations. Such dependencies are especially common in mobile platforms, where each manufacturer might differentiate the platform and provide value-add software and capabilities.
Historically, display drivers have used Int10 or other legacy methods to communicate with the system BIOS to enable features such as power management and brightness control.
However, to avoid the stability problems caused by legacy BIOS communication methods, the Windows Vista Display Driver Model (WDDM) does not support Int10 communications. As an alternative, WDDM display drivers have full access to ACPI methods to control the graphics hardware.
This paper describes the ACPI methods that can be used instead of Int10 to enable communication between the display driver and the system BIOS. Topics include:
- ACPI Methods for Display and BIOS Communications
- ACPI Notifications
- ACPI Method Evaluations
- BIOS Support
- Using ACPI Methods: Examples