Virtualbox WDDM之DxgkDdiQueryDeviceDescriptor

获取显示器的EDID

The DxgkDdiQueryDeviceDescriptor function returns a descriptor for a child device of a display adapter or for an external device (typically a monitor) connected to a child device of a display adapter.

https://msdn.microsoft.com/en-us/library/windows/hardware/ff559761(v=vs.85).aspx

为何不返回STATUS_MONITOR_NO_DESCRIPTOR

The child device identified byChildUid is connected to a monitor that does not support an EDID descriptor.

NTSTATUS DxgkDdiQueryDeviceDescriptor(    IN CONST PVOID MiniportDeviceContext,    IN ULONG ChildUid,    IN OUT PDXGK_DEVICE_DESCRIPTOR DeviceDescriptor    ){    /* The DxgkDdiQueryDeviceDescriptor should be made pageable. */    PAGED_CODE();    dfprintf(("==> "__FUNCTION__ ", context(0x%x)\n", MiniportDeviceContext));    /* we do not support EDID */    DeviceDescriptor->DescriptorOffset = 0;    DeviceDescriptor->DescriptorLength = 0;    DeviceDescriptor->DescriptorBuffer = NULL;    dfprintf(("<== "__FUNCTION__ ", context(0x%x)\n", MiniportDeviceContext));    return STATUS_SUCCESS;}