From owner-svn-src-all@FreeBSD.ORG Tue Nov 15 21:25:05 2011 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 9DDA6106564A; Tue, 15 Nov 2011 21:25:05 +0000 (UTC) (envelope-from hselasky@c2i.net) Received: from swip.net (mailfe05.c2i.net [212.247.154.130]) by mx1.freebsd.org (Postfix) with ESMTP id A04598FC12; Tue, 15 Nov 2011 21:25:04 +0000 (UTC) X-T2-Spam-Status: No, hits=2.5 required=5.0 tests=ALL_TRUSTED, BAYES_99 Received: from [188.126.198.129] (account mc467741@c2i.net HELO laptop002.hselasky.homeunix.org) by mailfe05.swip.net (CommuniGate Pro SMTP 5.2.19) with ESMTPA id 202171092; Tue, 15 Nov 2011 22:25:03 +0100 From: Hans Petter Selasky To: mdf@freebsd.org Date: Tue, 15 Nov 2011 22:22:17 +0100 User-Agent: KMail/1.13.5 (FreeBSD/8.2-STABLE; KDE/4.4.5; amd64; ; ) References: <201111152048.pAFKmvNC016452@svn.freebsd.org> <201111152202.24093.hselasky@c2i.net> In-Reply-To: X-Face: *nPdTl_}RuAI6^PVpA02T?$%Xa^>@hE0uyUIoiha$pC:9TVgl.Oq,NwSZ4V" =?iso-8859-1?q?=7CLR=2E+tj=7Dg5=0A=09=25V?=,x^qOs~mnU3]Gn; cQLv&.N>TrxmSFf+p6(30a/{)KUU!s}w\IhQBj}[g}bj0I3^glmC( =?iso-8859-1?q?=0A=09=3AAuzV9=3A=2EhESm-x4h240C=609=3Dw?= MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201111152222.17549.hselasky@c2i.net> Cc: "svn-src-head@freebsd.org" , "svn-src-all@freebsd.org" , "src-committers@freebsd.org" Subject: Re: svn commit: r227541 - head/sys/dev/usb/controller X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 15 Nov 2011 21:25:05 -0000 On Tuesday 15 November 2011 22:20:18 mdf@freebsd.org wrote: > On Tue, Nov 15, 2011 at 1:02 PM, Hans Petter Selasky wrote: > > For USB compliant operation, the USB stack requires hz to be greater or > > equal to 250 hz, to put it like that. Mostly a requirement in USB > > gadget/device mode. > > Really? That's news to me. Is that documented somewhere? I know we > still use hz=100 internally, but we're on stable/7 still so not using > the new USB stack yet. No it is not documented anywhere. This delay is mostly critical if you enable USB power saving features like suspend and resume. Then there are some software timers which should not derive too much. Most of the time the delays in USB are not critical. Transfer timers are in the seconds range and that works fine with hz=100. Where and how should I document such are requirement? Add something during system init? if (hz < 250) printf("USB: hz is too low (ignored)\n"); --HPS