Prior to this patch, osmo-trx relied totally on proper VTY configuration
being set in "rssi-offset" together with the RxGain set through TRXC in
order to provide correct Uplink RSSI measurements to bts-trx.
With this patch, RSSI is now by default calculated (in LMS and UHD
backends) based on the currently set RxGain, by providing empirically
discovered values. Still, for backward compatibility, the old
"rssi-offset" command will overwrite completely the per-default
calculated rssi offset.
A new optional parameter "relative" is added at the end of the
"rssi-offset" VTY command to flag the value as relative to the newly
per-default calculated value. This way specific setups (like adding a
LNA / RF fronted) can still be expressed while still keeping the
automatic per-default offset.
Related: OS#4468
Change-Id: I8ef78fd20c22c60d61bfb18d80a4a36df4fd6c20
Pau Espin
e91544d740