Threading and Synchronization Level Two

Level Two threading and synchronization is the same as Level Three, except that video memory is not evicted to host CPU memory. In other words, WDDM guarantees that:

• Only a single thread (the calling thread) is within the display miniport driver.
• The graphics hardware is idle.
• No direct memory access (DMA) buffers are currently being processed by the driver or passed through the GPU scheduler.

In order for some calls to be made under Level Two, the HardwareAccess flag must be set within the D3DDDI_ESCAPEFLAGS structure that is a member of DXGKARG_ESCAPE. If this flag is not set, then the call will fail.

The following list contains some of the calls into the display miniport driver that are made under Level Two:

• DxgkDdiCommitVidPn

• DxgkDdiControlInterrupt

• DxgkDdiDispatchIoRequest

• DxgkDdiEscape

• DxgkDdiNotifyAcpiEvent

• DxgkDdiQueryInterface

• DxgkDdiRecommendFunctionalVidPn

• DxgkDdiRecommendMonitorModes

• DxgkDdiSetPalette

• DxgkDdiSetTimingsFromVidPn

• DxgkDdiSetVidPnSourceAddress

• DxgkDdiSetVidPnSourceVisibility

• DxgkDdiUpdateActiveVidPnPresentPath