About DMA Device Support

Some display devices can perform blit operations (or other operations) on system memory surfaces. These operations are commonly referred to as Direct Memory Access (DMA) operations. You can exploit DMA support to accelerate certain combinations of operations. For example, on such a device, you could perform a blit from system memory to video memory while using the processor to prepare the next frame. In order to use such facilities, you must assume certain responsibilities. This section details these tasks.