Following is a list of ordering rules that apply to the Root Complex, Switches, and Bridges.
Locked Requests which are completed with a status other than Successful Completion do not establish lock.
Regardless of the status of any of the Completions associated with a locked sequence, all locked sequences and attempted locked sequences must be terminated by the transmission of an Unlock Message.
MRdLk, CplDLk and Unlock semantics are allowed only for the default Traffic Class (TC0).
Only one locked transaction sequence attempt may be in progress at a given time within a single hierarchy domain.
Any device which is not involved in the locked sequence must ...