Instrumentation

Option: --ddc

If option --ddc is specified, ddcutil reports protocol errors that it detects. These may reflect I2C bus errors, or deviations by monitors from the MCCS specfication. Most I2C errors cause a retry. Most monitors are very clean. Some, particularly older monitors, are very dirty.

Option: --statistics   [<stats-type]

Can be written as --stats. This option causes ddcutil to report execution statistics. It takes the following optional arguments:

Argument	Action
tries	Report retry statistics
errors	Report I2C/DDC error counts
calls	Report system call counts and time
elapsed	Report elapsed time summary
time	Synonum for elapsed
all	Report all statistics (default)

--stats calls implies --stats elapsed

Statistics can be voluminous. To see only the elapsed execution time, use argument ELAPSED (alternatively TIME). For example

$ ddcutil detect --stats elapsed

Note: --stats tries seperately reports multi-part read and multi-part write tries. This reflects how statistics are implementated. As a practical matter, no monitor has ever been seen that has features of type Table, so the multi-part write statistics will always be zero.

Per-thread statistics

Statistics are now broken down by thread. This is primarily of use in the shared library. These additional per-thread statistics are shown when --verbose is specified along with --stats.