[Feature Request] LP mode not dependent on two-way comms

[evilC]

I have an FC with a lifted RX pad.
The OSD still works, however LP mode does not appear to work.
I have also seen this happen on a quad where the wire going from the RX pad on the FC has come off - the OSD still updates and says it has left LP mode, but the VTX has not actually exited LP mode.
My guess is that what is happening is something like the FC requests from the VTX what power level it should enter when it leaves LP mode, and if it does not receive a response, then it does not know what power level to request on arming, so does not send the request to change power level, but does update the OSD
ie the comms goes something like:
FC: What power level should I request on arming?
VTX: Responds 2
(On Arm): FC: Set power level 2

Could this not be refactored to:
(On Arm): FC: Leave LP mode

Surely the latter would only require one-way comms?

I am not sure why the OSD updates when the RX pad is not connected - at the very least, the OSD should NOT change power level on arm if LP mode does in fact require a two-way connection - it's most confusing that you are flying around, wondering why your signal is terrible, when your OSD shows you are not in LP mode. If the OSD still showed 25mw even when you armed, at least that would give you a clue that there was a comms problem between the FC and the VTX

[ligenxxxx]

• OSD only needs to connect FC tx -> VTX rx and enable the osd function of FC tx to work. The flow of OSD data is one-way.
• I assume the FC RX pad is damaged, meaning the FC cannot get messages from the VTX. VTX will request the working status of fc every once in a while. When it obtains quad armed or disarmed, it switches the corresponding power according to lp mode.
  Now VTX cannot obtain the working status of FC, which indeed causes lp mode to fail to exit.