Windows Display Driver Model

This differs from native threads on the CPU where one task cannot be interrupted and therefore can take longer than necessary and make the computer appear less responsive.

WDDM attempts to unify the experience across different vendors by controlling the execution of GPU tasks.

Drivers under Windows XP were free to deal with hardware faults as they saw fit either by reporting it to the user or by attempting to recover silently.

However, according to Microsoft as of 2009, only about 1–2 percent of the hardware running Windows Vista used the XDDM,[10] with the rest already WDDM capable.

Because there is no limit on the number of open windows, the video memory available may prove insufficient, necessitating virtualization.

As the window contents that DWM composes into the final desktop are generated by different processes, cross-process surface sharing is necessary.

Also, because there can be other DirectX applications running alongside DWM on the DWM-managed desktop, they must be able to access the GPU in a shared manner, necessitating scheduling.

Successful implementations of composited desktops were done before Windows Vista on other platforms such as Quartz, Compiz, WindowFX.

The approach that Microsoft attempted was to try to make sure WDDM was a unified experience across different GPUs from multiple vendors by standardizing their features and performance.

Windows Vista introduced WDDM 1.0 as a new display driver architecture designed to be better performing, more reliable, and support new technologies including HDCP.

[27][28] New features were first previewed at the Build 2011 conference and include performance improvements as well as support for stereoscopic 3D rendering and video playback.

Other major features include preemptive multitasking of the GPU with finer granularity (DMA buffer, primitive, triangle, pixel, or instruction-level),[29] reduced memory footprint, improved resource sharing, and faster timeout detection and recovery.

Driver feature additions include wireless displays (Miracast), YUV format ranges, cross-adapter resources and GPU engine enumeration capabilities.

The new API will do away with automatic resource-management and pipeline-management tasks and allow developers to take full low-level control of adapter memory and rendering states.

Direct addressing of video memory is still supported by WDDMv2 for graphics hardware that requires it, but that is considered a legacy case.

Windows 10 Anniversary Update (version 1607) includes WDDM 2.1, which supports Shader Model 6.0 (mandatory for feature levels 12_0 and 12_1),[44] and DXGI 1.5 which supports HDR10 - a 10-bit high dynamic range, wide gamut format[45] defined by ITU-T Rec.

Updates to display driver development in Windows 10 version 2004 include the following features:[59] Windows 10 Insider Preview Manganese included WDDM 2.8, but no driver was ever publicly demonstrated to support it and it has been skipped for "Iron" and "Cobalt" development releases.