Of the peripherals listed in the table, which could cause coherency problems with cache contents? What criteria

Question:

Of the peripherals listed in the table, which could cause coherency problems with cache contents? What criteria determine if coherency issues must be addressed?

Direct Memory Access (DMA) allows devices to access memory directly rather than working through the CPU. This can dramatically speed up the performance of peripherals, but adds complexity to memory system implementations. Explore DMA implications by answering the questions about the following peripherals. a. Mouse Controller b. Ethernet Controller