• It is strongly recommended that an Upstream Port invalidate its internal PTM context when any of the following occur. If ePTM is supported, then an Upstream Port must invalidate its internal PTM context when any of the following occur: ◦ A PTM Request is replayed. ◦ A duplicate PTM ResponseD TLP is received. ◦ The relationship between PTM Master Time and the Upstream Port’s local time changes, as determined by implementation specific criteria. For example, this may occur as a result of a transition to a non-D0 state or due to accumulated PPM drift. 翻译

• 强烈建议上游端口在发生以下任何情况时使其内部PTM上下文无效。如果支持ePTM，则在发生以下任何情况时，上游端口必须使其内部PTM上下文无效：
◦ 重播PTM请求。
◦ 收到重复的PTM ResponseD TLP。
◦ PTM主时间与上游端口本地时间之间的关系发生变化，根据实现特定的标准确定。例如，这可能是由于转换为非D0状态或由于累积的PPM漂移而发生的。