From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965239AbWFARes (ORCPT ); Thu, 1 Jun 2006 13:34:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965247AbWFARer (ORCPT ); Thu, 1 Jun 2006 13:34:47 -0400 Received: from rtr.ca ([64.26.128.89]:34254 "EHLO mail.rtr.ca") by vger.kernel.org with ESMTP id S965239AbWFARer (ORCPT ); Thu, 1 Jun 2006 13:34:47 -0400 Message-ID: <447F2536.9030904@rtr.ca> Date: Thu, 01 Jun 2006 13:34:46 -0400 From: Mark Lord User-Agent: Thunderbird 1.5.0.2 (X11/20060420) MIME-Version: 1.0 To: Andrew Morton Cc: David Liontooth , linux-kernel@vger.kernel.org, linux-usb-devel@lists.sourceforge.net, Alan Stern Subject: Re: USB devices fail unnecessarily on unpowered hubs References: <447EB0DC.4040203@cogweb.net> <20060601030140.172239b0.akpm@osdl.org> In-Reply-To: <20060601030140.172239b0.akpm@osdl.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andrew Morton wrote: > On Thu, 01 Jun 2006 02:18:20 -0700 > .. >> This is generating a lot of grief and appears to be unnecessarily >> strict. Common USB sticks with a MaxPower value just above 100mA, for >> instance, typically work fine on unpowered hubs supplying 100mA. >> >> Is a more user-friendly solution possible? Could the shortfall >> information be passed to udev, which would allow rules to be written per >> device? .. > Yes, it sounds like we're being non-real-worldly here. This change > apparently broke things. Did it actually fix anything as well? I think a far more sensible approach would be to just ensure that the total current draw for the (unpowered) hub and all connected devices, stays below the 500mA allowed. So a 200mA device could coexist with a 100mA device on a hub which itself steals 100mA. Cheers