Hello Steven.
You know more than me on this area.
My references are:
1) DevHlp_AddTraceEvent
-- "SMP Programming Addendum" on the "STRACE - DevHlp Functions"
-- sg244640: "Trace Events for DEVHELP Major Code: 0X0006, Sorted by Tracepoint"
--- OS) DevHlp_AddTraceEvent Post-Invocation 00132 (0X0084)
--- OS) DevHlp_AddTraceEvent Pre-Invocation 00004 (0X0004)
2) DevHlp_SysTrace
-- "Programming Guide and Reference Addendum" on the "Device Helper (DevHlp) Services and Function Codes" at "DevHlp_SysTrace".
There it says "DevHlp_SysTrace is synonymous with DevHlp_RAS."
On "devhlp.inc" from the DDK it has:
DevHlp_RAS EQU 40 ; 28 Put info in RAS trace buffer
DevHlp_SysTrace EQU 40 ; 28 Synonym for DevHlp_RAS f180062
This is why I guess that DevHlp_RAS and DevHlp_SysTrace are the same. No idea about "DevHlp_AddTraceEvent".
Regards
Looks like we are spinning around in circles:
you will realize that major trace code 0x0006 neither lists DevHlp_RAS nor DevHlp_SysTrace. That said, it looks like DevHlp_AddTraceEvent = DevHlp_RAS = DevHlp_SysTrace as that is what this devhelp does: it adds a trace event to the trace buffer.