From owner-freebsd-questions@FreeBSD.ORG Fri Apr 9 20:39:24 2010 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 819B6106566B for ; Fri, 9 Apr 2010 20:39:24 +0000 (UTC) (envelope-from wblock@wonkity.com) Received: from wonkity.com (wonkity.com [67.158.26.137]) by mx1.freebsd.org (Postfix) with ESMTP id 1AD448FC0A for ; Fri, 9 Apr 2010 20:39:23 +0000 (UTC) Received: from wonkity.com (localhost [127.0.0.1]) by wonkity.com (8.14.3/8.14.3) with ESMTP id o39KO5ep048767 for ; Fri, 9 Apr 2010 14:24:05 -0600 (MDT) (envelope-from wblock@wonkity.com) Received: from localhost (wblock@localhost) by wonkity.com (8.14.3/8.14.3/Submit) with ESMTP id o39KO5rY048764 for ; Fri, 9 Apr 2010 14:24:05 -0600 (MDT) (envelope-from wblock@wonkity.com) Date: Fri, 9 Apr 2010 14:24:05 -0600 (MDT) From: Warren Block To: FreeBSD Questions In-Reply-To: <4BBF727D.6000407@joseph-a-nagy-jr.us> Message-ID: References: <4BBE8DB1.8040905@joseph-a-nagy-jr.us> <4BBE9470.1040607@joseph-a-nagy-jr.us> <4BBEB5BC.3000509@joseph-a-nagy-jr.us> <4bbedc81.G0j71lonOCUqR/vZ%perryh@pluto.rain.com> <4BBF2674.6080402@joseph-a-nagy-jr.us> <4BBF727D.6000407@joseph-a-nagy-jr.us> User-Agent: Alpine 2.00 (BSF 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (wonkity.com [127.0.0.1]); Fri, 09 Apr 2010 14:24:05 -0600 (MDT) Subject: Re: USB Powered Speakers X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 09 Apr 2010 20:39:24 -0000 On Fri, 9 Apr 2010, Programmer In Training wrote: > On 04/09/10 10:15, Brodey Dover wrote: >> "Apr 8 22:30:16 heaven kernel: usb_alloc_device:1624: getting device >> descriptor at addr 3 failed, USB_ERR_IOERROR!" >> >> exactly! That is what is causing the issues. From what I can see, it >> is like it was explained before. The OS has chosen to play nice and >> request that the speakers are disabled. >> >> The power requirements will not affect the system until the speakers >> are producing sound. In other words, the system will only draw UP to >> the power input rating while in operation. At idle, I'd wager they may >> only use 1/10 of its power rating for the idle ICs and a power LED. Just to add: When you plug in a USB device, it is a "low power" device (single unit load, 100 mA) by default. If that device wants to draw more power, it has to request high power (5 unit loads) from the hub. The hub can provide that power, or shut down the port. > Only it's not the speakers that have their operation interrupted, JUST > the keyboard (not even the mouse is affected). Guesses: Total power budget (but FIFO?). Speaker/keyboard USB ports are on the same internal hub. High-power OLED keyboard (my eyes!). Speakers labelled 500 mA but really only a low-power USB device. -Warren Block * Rapid City, South Dakota USA