This was not an issue with the original FIFO code, which dynamically
substituted frames and always created the minimal required backlog.
The RIFO can by principle not operate this way, so we really have to
prime / pre-fill it with a number of TDM frames. That initial fill
level has to be sufficient to cover RTT jitter of the OCTOI link as
well as clock drift between (GPS synced) receiver and transmitter.
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
Change-Id: I3a4b3846d3dbd1c99989e994ad95e609f2757219