NetBSD and CH340 usb/serial

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

Hello,
I have this device:
https://www.olimex.com/Products/Breadboarding/BB-CH340T/open-source-hardware
which is detected by NetBSD as:
uchcom0 at uhub2 port 3
uchcom0: QinHeng Electronics USB2.0-Serial, rev 1.10/2.54, addr 11
uchcom0: CH341 detected
ucom2 at uchcom0

AFAIK (it's light-gray on gray) the chip is marked H340T, so it's probably
misdetected as H341 but reading the driver sources it shouldn't make
a difference.

The problem is it doesnt' work. If I connected a known-working serial TX to
the CH340 rx uchcom0 doesn't receive anything (used with cu).
If I connect the CH340 tx to a known-working serial RX, I get characters
but with bit changes which usually indicates a speed mismatch between
transmitter and receiver (both are at 9600bps).
trying speeds between 4800 and 57600 on the uchcom0 side doens't give
me a working transmit.

Does anyone know what could be missing in our driver ?

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--