I know this is old by now, but I still hasn’t found a technical description of the “hardware scheduler” that WDDM requires. Is it related to the “lost device” error in old DirectX pre-WDDM?
Background: The old XPDM driver model allow only one app to use the GPU at a time. If another app tries to use it, the current app receives a “lost device” error on the next DirectX call. This would have been unacceptable for the DWM if it was to do desktop composition and run DirectX apps at the same time. Obviously to allow the DWM to work, it require a way to allow multiple apps to use DirectX at the same time. Is that what the “hardware scheduler” does?