Hi.
I noticed today that multiple of my CH341 USB to serial adapters don't
work as expected. They attach and are detected properly, but with `cu`
or any other serial terminal emulator I cannot communicate with other
end.
uchcom0 at uhub0 port 4 configuration 1 interface 0 "QinHeng Electronics
USB2.0-Ser!" rev 1.10/2.54 addr 2
uchcom0: CH341
ucom0 at uchcom0: usb0.0.00004.0
I get mainly underscore characters:
# cu -s 115200 -l /dev/cuaU0
Connected to /dev/cuaU0 (speed 115200)
_____l____fff"&_?_ynJ___I____)_____4________.__________________l_____
However, when I revert uchcom.c -r1.39 back to -r1.38 my CH341 works
correctly again.
Tested on:
OpenBSD 7.8-current (GENERIC.MP) #98: Sun Nov 16 08:46:59 MST 2025
[email protected]:/usr/src/sys/arch/amd64/compile/GENERIC.MP
but also on 7.7-stable and 7.8-stable.
7.8-current -> broken
7.8-stable -> broken
7.7-stable -> works
7.8-current with uchcom.c -r1.38 -> works
--
Regards,
Mikolaj
