psarc/2009/197 - UFTDI - fast-track

[James Carlson]

Tim Marsland writes:
> James Carlson wrote:
> > (The better answer is for the driver to supply the default: if the
> > hardware is known to be deficient or otherwise "special," then using
> > ignore-cd=1 as the default is fine.  If it's known to be a properly
> > functioning serial port with a reasonble complement of modem control
> > lines, then it should be ignore-cd=0.)
> 
> I was really trying to capture the class of USB serial devices that
> are mostly *not* used in the role of modems.   Which increasingly
> seems to be all of them, as modems become an increasingly arcane
> concept except for debugging and low-level hardware hacking.

In contrast, *all* of the USB serial devices (three different brands
so far) I've been able to use on Solaris are USB-to-DB9 affairs with
full modem controls.  Go figure.  ;-}

> However, if you want to restrict that statement to the
> usbftdi driver, I'm fine with that too.

OK.  If it turns out that nobody ever manufactures a DCD wire again,
then we can certainly yank support later.

(For what it's worth, just because they're called "modem controls,"
they're not just for modems.  For instance, on a V.120 TA, it's not
uncommon for DCD to be wired into the protocol negotiation, so that
you get carrier when the circuit is live, even though there's no
"modem" involved.)

-- 
James Carlson, Solaris Networking              <james.d.carlson at sun.com>
Sun Microsystems / 35 Network Drive        71.232W   Vox +1 781 442 2084
MS UBUR02-212 / Burlington MA 01803-2757   42.496N   Fax +1 781 442 1677