I am studying the AXI4 version H_c specification. I do not understand the content of the chapter "A6: AXI Ordering Model".
In particular, "A6.4 Observation and Completion Definitions" is difficult to understand. The word observation is too abstract for me. I think that a transaction is either a command or data. This specification states that a transaction is observing another transaction. I don't understand the mean of the word.
Please tell me what this word means for a transaction, and what part of AXI it applies to.