DXGK_VIDSCHCAPS structure (d3dkmddi.h)
The DXGK_VIDSCHCAPS structure has bit-field flags that identify the GPU's scheduling capabilities that a kernel-mode display miniport driver (KMD) can support.
Syntax
typedef struct _DXGK_VIDSCHCAPS {
union {
struct {
UINT MultiEngineAware : 1;
UINT VSyncPowerSaveAware : 1;
UINT PreemptionAware : 1;
UINT NoDmaPatching : 1;
UINT CancelCommandAware : 1;
UINT No64BitAtomics : 1;
UINT LowIrqlPreemptCommand : 1;
UINT HwQueuePacketCap : 4;
UINT NativeGpuFence : 1;
UINT OptimizedNativeFenceSignaledInterrupt : 1;
#if ...
UINT Reserved : 19;
#elif
UINT Reserved : 21;
#elif
UINT Reserved : 25;
#elif
UINT Reserved : 27;
#else
UINT Reserved : 30;
#endif
};
UINT Value;
};
} DXGK_VIDSCHCAPS;
Members
MultiEngineAware
A UINT value that specifies whether the driver supports the creation and destruction of a device context (through the DxgkDdiCreateContext and DxgkDdiDestroyContext functions) and the use of a device context (through the DxgkDdiPresent and DxgkDdiRender functions). If the driver does not support context creation, for every call to the driver that would pass a handle to a context, the Microsoft DirectX graphics kernel subsystem replaces the handle to the context with a handle to the device.
VSyncPowerSaveAware
A UINT value that specifies whether the driver supports vertical-sync power-saving functionality.
If VSyncPowerSaveAware is set to 1 (TRUE), the OS can save power by disabling and enabling the vertical-sync interrupt that occurs from the usage of some applications. If VSyncPowerSaveAware is set to zero (FALSE), the OS will never disable the vertical-sync interrupt for applications that might cause the vertical-sync interrupt to occur. Supported starting with Windows Server 2008 and Windows Vista with SP1.
PreemptionAware
A UINT value that specifies whether the driver supports the GPU preemption policy of Windows 8 and later versions of Windows. With this policy, the OS always issues preemption requests to the GPU before it initiates the **Timeout Detection and Recovery (TDR) process. Supported starting with Windows 8.
If PreemptionAware is set to 1 (TRUE), the driver supports the preemption policy of Windows 8 and later versions of Windows. Note that if PreemptionAware is set to 1, the MultiEngineAware member must also be set to a value of 1. If PreemptionAware is set to 1 but MultiEngineAware is set to zero, the OS will halt the driver initialization process and return a failure code.
If PreemptionAware is set to zero (FALSE), the driver supports the preemption policy of Windows 7. With this policy, the OS may not issue preemption requests while potentially long running operations are being executed on the GPU. As a result, these GPU requests are not preempted before the TDR process is initiated. This may cause the TDR process to repeatedly reset the GPU which could lead to a system stop error.
NoDmaPatching
A UINT value that specifies whether the driver disables leak detection for DMA buffers that are split into multiple parts. This detection is performed after the driver's DxgkDdiPatch function is called to assign, or patch, physical addresses to each part of the DMA buffer. Supported starting with Windows 8.
Display devices that support virtual addresses can reprogram a virtual address to a new video memory location without having to patch the value of the DMA buffer address. For these types of display devices, the driver should set NoDmaPatching to 1.
If NoDmaPatching is set to 1 (TRUE), the driver disables leak detection, and the behavior of DMA buffer splitting is the same as in Windows 7. Note that when NoDmaPatching is set to 1, the PreemptionAware and MultiEngineAware members must also be set to 1. If NoDmaPatching is set to 1 but PreemptionAware or MultiEngineAware are set to zero, the OS will halt the driver initialization process and return a failure code.
If NoDmaPatching is set to 0 (FALSE), the driver enables leak detection for patched DMA buffer addresses. The OS performs leak detection before it calls the driver's DxgkDdiPatch function.
CancelCommandAware
A UINT value that specifies whether the driver supports cleaning up internal resources (through the DxgkDdiCancelCommand function) after a command is removed from the hardware queue. Supported starting with Windows 8.
If CancelCommandAware is set to 1 (TRUE), the driver supports cleaning up resources associated with a canceled DMA packet. Note that when CancelCommandAware is set to 1, the MultiEngineAware member must also be set to 1. If CancelCommandAware is set to 1 but MultiEngineAware is set to zero, the OS returns a failure code.
If CancelCommandAware is set to zero (FALSE), the driver does not support cleaning up resources.
No64BitAtomics
If No64BitAtomics is set to 1 (TRUE), the driver indicates that the GPU is capable of only updating 32 bit values atomically. In this case, the OS will handle the fence wraparound case automatically, however it will place a restriction that an outstanding wait and signal fence values cannot be more than UINT_MAX/2 apart from the last signaled fence value. Supported starting with Windows 10.
If No64BitAtomics is set to zero (FALSE), the driver indicates that the GPU is capable of updating 64 bit values atomically as visible by the CPU.
LowIrqlPreemptCommand
HwQueuePacketCap
Maximum number of DMA packets allowed to be queued to a node.
NativeGpuFence
If the OS has enabled the DXGK_FEATURE_NATIVE_FENCE feature, the driver can declare support for native GPU fence functionality during adapter initialization by setting the NativeGpuFence bit to 1. This capability is exposed to user mode via a corresponding D3DKMT_WDDM_3_1_CAPS::NativeGpuFenceSupported bit. For more information, see Native GPU fence objects. Available starting with Windows 11, version 22H2 (WDDM 3.1).
OptimizedNativeFenceSignaledInterrupt
The driver sets this TRUE if, on a signaled interrupt, the GPU can specify in DXGKARGCB_NOTIFY_INTERRUPT_DATA::NativeFenceSignaled only the KMD handle of the HWQueue that was running. For more information, see Native GPU fence objects. Available starting with Windows 11, version 22H2 (WDDM 3.1).
Reserved
This member is reserved and should be set to zero.
Value
An alternative way to access the bit-field flags in the union.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows Vista |
| Header | d3dkmddi.h (include D3dkmddi.h) |