The asix-sigma driver does support triggers, including pre-trigger capture ratio and all combinations of optional acquisition time and sample count limits. The current implementation errs on the safe side, and provides at least the requested amount of data, but does not enforce the exact sample count limit when specified and triggers were involved. The proper approach would be to not re-invent the required logic, but instead re-use common soft-trigger support for session feed submission with queued sample data before the trigger position.