>Number:         12627
>Category:       kern
>Synopsis:       usb mct modem control lines get stuck
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Apr 13 05:39:00 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator:     Wolfgang Rupprecht
>Release:        NetBSD-current Apr/10/2001
>Organization:
W S Rupprecht Computer Consulting, Fremont CA
>Environment:
System: NetBSD capsicum.wsrcc.com 1.5U NetBSD 1.5U (WSRCC_ATHLON) #10: Tue Apr 10 10:32:50 PDT 2001     wolfgang@capsicum.wsrcc.com:/v/src/netbsd/src/sys/arch/i386/compile/WSRCC_ATHLON i386

Architecture: i386
Machine: i386
>Description:
	
	(thanks for adding the USB MCT driver.  It's great to finally
	have more tty lines!)

	Observed on a Dlink DSB-S25.

	The first opening of the MCT as /dev/ttyU0 will work as
	expected.  If the process is killed then the next opening of 
	tty line will fail to correctly assert the RTS line.  It will
	stay unasserted.

	Just as strange is that the modem control lines are all
	asserted just after the USB device is plugged in, before any
	process is listening to the tty port.  I would have expected
	the tty port's modem lines to come up de-asserted until the
	tty is opened.

>How-To-Repeat:

	Plug a led RS232 tester into the MCT.

	Run a process that essentially does an open with all the
	termios flags clear and only these c_cflags set.
	 
	    termios.c_cflag = CS8 | CLOCAL | CREAD;

	Run a second time.

	One work-around is to unplug the USB cable when the tty 
	is closed.  It will eventually clear things out.
 	
>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: