If we perform the downlink calibration too early, the TRF6151 might
not yet provide a stable signal and we'll not be able to receive
anything.
From the desired "BDLENA" time, we subtract all the delays and
latencies to determine the point in time at which the calibration
process should start.
In the sercomm_cons layer, ee used to enqueue a msgb for sending
every time there is an end-of-line. However, if we send a number
of very short lines, we easily run out of msgbs.
Now we check how much msgb backlog there is in the transmit queue,
and decide to skip the end-of-line flushing if needed.
This still doesn't solve all our problems, but its still a useful
mechanism.
The cause is really not clear. The formual using 2*Pi to convert
from radians to frequency is perfectly correct.
However, measurements with various test equipment (including Racal 6103)
have shown our frequency error estimate is always off by a power of two...
Harald Welte