USB-to-serial adapter no longer working in 8.0-RC1

Greg Rivers gcr+freebsd-current at
Sat Sep 19 03:40:31 UTC 2009

Last May, Hans Petter Selasky fixed up the umct driver for 8.0-CURRENT 
After updating to 8.0-RC1 I find that the driver has a new problem.

Testing with cu(1) and a modem, I can see by watching the lights on the 
modem and on the usb-serial adapter that it still asserts DTR and sends 
and receives characters properly, but no characters reach the terminal. 
That seems to be the only problem: characters from the attached serial 
device seem to disappear before reaching whatever program has the serial 
device open.  But strangely enough, power cycling the modem results in a 
few "line noise" characters appearing.  Perhaps the driver is no longer 
responding appropriately to DSR?

Any insight or troubleshooting clues would be much appreciated.

Greg Rivers

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