Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764331AbYBNUS3 (ORCPT ); Thu, 14 Feb 2008 15:18:29 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761051AbYBNUSR (ORCPT ); Thu, 14 Feb 2008 15:18:17 -0500 Received: from vms040pub.verizon.net ([206.46.252.40]:55476 "EHLO vms040pub.verizon.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760926AbYBNUSQ (ORCPT ); Thu, 14 Feb 2008 15:18:16 -0500 Date: Thu, 14 Feb 2008 15:04:41 -0500 From: Gene Heskett Subject: Re: Handshaking on USB serial devices In-reply-to: <20080214193731.3c36acb0@core> To: Alan Cox Cc: David Newall , Greg KH , linux-usb@vger.kernel.org, Linux Kernel Mailing List Message-id: <200802141504.41991.gene.heskett@gmail.com> Organization: Organization? very little MIME-version: 1.0 Content-type: text/plain; charset=iso-8859-1 Content-transfer-encoding: 7bit Content-disposition: inline References: <47B30291.2040905@davidnewall.com> <200802141255.22048.gene.heskett@gmail.com> <20080214193731.3c36acb0@core> User-Agent: KMail/1.9.6 (enterprise 0.20071204.744707) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1285 Lines: 28 On Thursday 14 February 2008, Alan Cox wrote: >> byte of a packet is being thrown away about .1% of the time for the >> pl2303, but I'm not sure if the FTDI driver still suffers from a similar >> rash. I > >A 20 byte low speed message is too small for flow control to account for >it. Where then could the first byte go? Note I'm not fussing about flow controls per sei, so the subject line maybe needs to be adjusted, but they obviously work well enough that a multimegabyte transfer to my printer works very well, but about usb trying to entirely replace serial here. There does seem to be a problem but I'm not 100% positive where it is in the chain of a usb packets travels. What I've observed, with hidraw I think it was, is that the first 'wake up' byte incoming didn't seem to be there. -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Whenever people agree with me I always feel I must be wrong. -- Oscar Wilde -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/