Dear Maintainer,

I Use a MosChip 9845 serial card. The first serial port on this card is
connected to a Conrad DCF77 receiver. With kernel 6.1.0-54-amd64 the
receiver doesn't work; With errors like 'INCOMPLETE DATA - time code only
has 3 bits' and 'parity check FAILED for'. Errors like these are usually
the result of radio interference. However, A RS232 tester (with red and
green LEDs) shows no erratic flashing.

I kind of tried but failed to replicate these errors.
A null modem cable with two instances of Minicom just works. It also works
with a low baud rate (300) and settings similar to that of NTPDs DCF
driver: 8 bits and even parity.
I just happened to have some simple serial port software that I modified to
run at 50 baud, 8 bits and even parity. Sending one byte ASCII per second
also works. Even binary data works.

Dumping the data from the DCF receiver to a file is an other story.
With an older kernel I get 0x00 (200 ms pulse) or 0xf0 (100 ms pulse), one
per second.
With kernel 6.1.0-54-amd64 I get much more data. As if the same data
is being read over and over again.

Kind regards,
Rob