SPRUJ28E November 2021 – September 2024 AM68 , AM68A , TDA4AL-Q1 , TDA4VE-Q1 , TDA4VL-Q1
As an End Point, the PCIe subsystem does not need to stay operational when the device reset is happening. Upon detecting the link disconnection, the upstream port will re-train the link when Root Port issues a link retrain command to itself or to a switch port next to the EP.
If it is required that the PCIe subsystem be operational (without any transactions though), the End Point must negotiate with the other devices (primarily Root Port) to stop activity. Otherwise, if the End Point goes into force idle/standby or clock stop modes without properly managing the process, there will be timeouts or errors on incoming read transactions and writes will be completely lost. In such situation, the Root Port will encounter excessive errors and may issue a hot reset to the End Point anyway.