| 摘要 |
A data processing apparatus comprises a first agent generating a cache dormant indication when a cache is in a dormant state, and a second agent which issues cache maintenance requests for data stored in the first agents cache. In response to the cache dormant indication generated by the first agent, the second agent may suppress issuing cache maintenance requests for the first agents cache. The cache may be in the dormant state when the cache stores: no valid data, and there are no outstanding transactions; no dirty data; no valid data relevant to the second agent; and/or no valid data of at least one predetermined category. The cache may be in the dormant state when the cache is in a power saving state, and may indicate this by setting a flag in a storage location accessible to the second agent, and/or by asserting a hardware signal, and/or transmitting a message to the second agent. The cache maintenance requests may be snoop requests, clean requests to trigger dirty-data writeback from the cache to memory, and invalidate requests to invalidate data in the cache. The first and second agents may comprise the same processing device. |
