From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f175.google.com (mail-wi0-f175.google.com [209.85.212.175]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id 87EF72004D7 for ; Wed, 14 Mar 2012 11:57:08 -0700 (PDT) Received: by wibhn6 with SMTP id hn6so6958800wib.10 for ; Wed, 14 Mar 2012 11:57:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; bh=XgQGLLSGwnAXUfhvnXGXBubu5ozUh75JLhOEHTsOsXU=; b=isLp6rz+1gFhUNijG3FEyJQ+QizRRIi1m+RsIwqmDLUf15jXDQrx7btIFz86gf2yQh 6dJW/BRu+KWOaEypMWuH4SpjNpZka+8kIYPwDN9p1vZz5FVVYn5XHBTQ2iMeN4A+/4Ua aTMW9BcGTiBFx4Hq6Cfmo31o6k5M4n5XotoXjPk0CfjT6osEJz3/OPlFJm+3I+aMNiYN LJjBRdJKrLjm2yGlMeLIS2ipytb+0uFkc2E3aPuXiIQjXkRIL75gCPKO9HnCl95gYT8V 8i9kSMGL5PyWho4W31XZCO84qb9grSgVqshjHwEZlUzW8RpvpBYI8EJz33jNgar//LlH 3lZw== MIME-Version: 1.0 Received: by 10.180.106.9 with SMTP id gq9mr8887183wib.17.1331751426179; Wed, 14 Mar 2012 11:57:06 -0700 (PDT) Received: by 10.223.151.8 with HTTP; Wed, 14 Mar 2012 11:57:06 -0700 (PDT) In-Reply-To: <20120314184258.GA30210@thyrsus.com> References: <20120314104920.697EA40617@snark.thyrsus.com> <20120314184258.GA30210@thyrsus.com> Date: Wed, 14 Mar 2012 11:57:06 -0700 Message-ID: From: Dave Taht To: esr@thyrsus.com Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Cc: thumbgps-devel@lists.bufferbloat.net, Andrew McGregor Subject: Re: [Thumbgps-devel] USB handshake signals and Linux X-BeenThere: thumbgps-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 14 Mar 2012 18:57:09 -0000 On Wed, Mar 14, 2012 at 11:42 AM, Eric S. Raymond wrote: > Patrick Maupin : >> The FTDI devices have a latency timer that allows you to control this >> somewhat. > In a private chat late last night andrew mentioned that the ftdi devices were extensively reprogrammable, in that they came as a usb device but were really, underneath, just a bunch of gpios... > I found a couple of hits on the search "PL2303 latency timer" that > implies it has one too. =A0But I doubt the value of the latency timer > will be relevant for handshake-line notifications; see below. > >> =A0 =A0 =A0 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. =A0We might need to characterize "ASAP" but I would hope that it >> doesn't vary too much. > > Probably not. =A0Trying 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. > -- > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Eric= S. Raymond > _______________________________________________ > Thumbgps-devel mailing list > Thumbgps-devel@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/thumbgps-devel --=20 Dave T=E4ht SKYPE: davetaht US Tel: 1-239-829-5608 http://www.bufferbloat.net