util/spkmodem-decode: automatic tone calibration

current logic is hardcoded, as in the original spkmodem-recv.

with this change, small differences are observed and averaged,
then the detection thresholds are adjusted accordingly.

the existing macros serve as a baseline, but real signals
differ. with this change, we therefore account for possible
drift in timings, which can change in real-time; the old
code could possibly get out of sync beccause of that, which
may have resulted in corrupt characters on the screen. this
change therefore should make the output a bit more stable.

the detection window is continually adjusted, so that the
output timings don't drift.

the tolerances are automatically adjusted based on base
timings (see new define in patch)

Signed-off-by: Leah Rowe <leah@libreboot.org>

0 files changed, 0 insertions, 0 deletions