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List:       freebsd-hackers
Subject:    Re: Getting nonstandard serial baud rates w/FTDI
From:       Bernd Walter <ticso () cicely12 ! cicely ! de>
Date:       2007-10-25 21:16:49
Message-ID: 20071025211649.GB46533 () cicely12 ! cicely ! de
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On Thu, Oct 25, 2007 at 08:52:48AM -0700, Brooks Talley wrote:
> Thanks to everyone who applied.  The OpenBSD approach to setting UFTDI baud rates \
> is definitely superior. 
> However, the root of my problem turned out to be Python.  Even with the new baud \
> rate hardcoded in the UFTDI kernel module and manually added to termios.h, Python \
> was refusing to admit that it was a valid baud rate. 
> The issue is that Python (2.5.1) compiles its own termios interface module, which \
> builds a list of allowed baud rates from the defines in termios.h.  Python's \
> termios.c does something like this: 
> include <termios.h>
> termios_constants[] = {
> {"B300",B300},
> {"B1200",B1200},
> {"B2400",B2400},
> .
> .
> .
> #ifdef B115200
> {"B115200",B115200}
> #endif
> #ifdef B230400
> {"B230400",B230400}
> #endif
> 
> So of course my new buad rate never got added to the list.  It's a fairly ugly \
> problem, because the valud baud rates are set in #defines in termios.h and Python \
> wants an array of them, and of course there's no way (that I know of) to enumerate \
> defines and get a list of those that start with "B" followed by numbers (and, of \
> course, for all I know there's some other BXXXXX define somewhere that is not \
> intended to indicate an allowed baud rate). 
> The real solution would be to use the OpenBSD UFTDI baud rate generator and update \
> Python's termios.c to avoid the list of valid baud rates and have it just ask the \
> serial port to set the requested rate and report back any error.  But that requires \
> far more than my meager skills.  I just added another hardcoded #ifdef to Python's \
> termios.c and it is all working now.

I will take care about the ftdi driver within the next days, but will
not MFC it until the releases are done.
The python part is left for someone else.

-- 
B.Walter                http://www.bwct.de      http://www.fizon.de
bernd@bwct.de           info@bwct.de            support@fizon.de
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