From: "Eric S. Raymond" <esr@thyrsus.com>
To: Patrick Maupin <pmaupin@gmail.com>
Cc: thumbgps-devel@lists.bufferbloat.net
Subject: Re: [Thumbgps-devel] USB handshake signals and Linux
Date: Wed, 14 Mar 2012 14:42:58 -0400 [thread overview]
Message-ID: <20120314184258.GA30210@thyrsus.com> (raw)
In-Reply-To: <CAPz3yKc96S8GqeGMVa1z35=w4zb9X_HmNypwz6GVNGbVdJ0D6g@mail.gmail.com>
Patrick Maupin <pmaupin@gmail.com>:
> The FTDI devices have a latency timer that allows you to control this
> somewhat.
I found a couple of hits on the search "PL2303 latency timer" that
implies it has one too. But I doubt the value of the latency timer
will be relevant for handshake-line notifications; see below.
> But even better, if we're going to use the PPS signal, they
> essentially guarantee that they will send ASAP on modem control signal
> change. We might need to characterize "ASAP" but I would hope that it
> doesn't vary too much.
Probably not. Trying to buffer a handshake state change doesn't make
any sense. I'm not surprised that the FTDI gives them realtime
priority and I *will* be surprised if the PL2303 (or any other
adapter) doesn't do likewise.
--
<a href="http://www.catb.org/~esr/">Eric S. Raymond</a>
next prev parent reply other threads:[~2012-03-14 18:43 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-14 10:49 Eric S. Raymond
2012-03-14 12:55 ` Ron Frazier (NTP)
2012-03-14 12:58 ` Ron Frazier (NTP)
2012-03-14 18:13 ` Patrick Maupin
2012-03-14 18:42 ` Eric S. Raymond [this message]
2012-03-14 18:57 ` Dave Taht
2012-03-14 20:09 ` Patrick Maupin
2012-03-15 3:33 ` Patrick Maupin
2012-03-15 4:23 ` Eric S. Raymond
[not found] <CAFv7OigTLhw24i+jRshv0YgLogyx_GEREAOkP7tieeH1Nr5WzA@mail.gmail.com>
2012-03-15 14:37 ` tz
2012-03-15 14:52 ` Ron Frazier (NTP)
2012-03-15 17:57 ` Eric S. Raymond
2012-03-15 18:31 ` Eric S. Raymond
2012-03-15 18:54 ` Patrick Maupin
2012-03-15 19:36 ` Eric S. Raymond
2012-03-15 19:55 ` Patrick Maupin
2012-03-15 19:14 ` tz
2012-03-15 19:50 ` Eric S. Raymond
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