From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lan Tianyu Subject: Re: [RFC PATCH] usb/acpi: Add support usb port power off mechanism for device fixed on the motherboard Date: Wed, 16 May 2012 22:54:13 +0800 Message-ID: <4FB3BF95.50600@intel.com> References: <4FB348AB.5050308@intel.com> <20120516143958.GA612@kroah.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mga03.intel.com ([143.182.124.21]:39649 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753872Ab2EPOyR (ORCPT ); Wed, 16 May 2012 10:54:17 -0400 In-Reply-To: <20120516143958.GA612@kroah.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Greg KH Cc: Alan Stern , Sarah Sharp , Dan Williams , lenb@kernel.org, linux-acpi@vger.kernel.org, linux-usb@vger.kernel.org On 2012/5/16 22:39, Greg KH wrote: > On Wed, May 16, 2012 at 10:36:02AM -0400, Alan Stern wrote: >> On Wed, 16 May 2012, Lan Tianyu wrote: >> >>> Ok. Let me reconfirm the meaning of these opinions. >>> >>> "auto" >>> if port without device, turn off power directly. >>> if port with device, turn off power when the device is suspended. >>> >>> "on" the port's power must be on. >>> >>> "off" the port's power must be off. >>> >>> Right? >> Maybe the "auto" setting should be renamed "active". Then "auto" can >> be used for: >> >> If the port has a device, turn the power on. >> If the port doesn't have a device, turn the power off. > And plugging a new device into a port that was powered off is going to > cause the power to come back on, right? When the port was powered off, the connect-change event will not be detected and we don't know a device was plugged in. :( > > greg k-h -- Best Regards Tianyu Lan linux kernel enabling team