From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from canardo.mork.no ([148.122.252.1]:59023 "EHLO canardo.mork.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750828Ab2GYWhF convert rfc822-to-8bit (ORCPT ); Wed, 25 Jul 2012 18:37:05 -0400 From: =?utf-8?Q?Bj=C3=B8rn_Mork?= To: "Rafael J. Wysocki" Cc: Huang Ying , huang ying , Zheng Yan , Bjorn Helgaas , linux-pci@vger.kernel.org, linux-usb@vger.kernel.org, Alan Stern Subject: Re: bisected regression, v3.5 -> next-20120724: PCI PM causes USB hotplug failure References: <874now7xi8.fsf@nemi.mork.no> <201207252202.22302.rjw@sisk.pl> Date: Thu, 26 Jul 2012 00:36:45 +0200 In-Reply-To: <201207252202.22302.rjw@sisk.pl> (Rafael J. Wysocki's message of "Wed, 25 Jul 2012 22:02:22 +0200") Message-ID: <87pq7j79j6.fsf@nemi.mork.no> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Sender: linux-pci-owner@vger.kernel.org List-ID: "Rafael J. Wysocki" writes: > This is not really necessary. The problem is the change of behavior I was > worried about some time ago. > > Namely, the device in question apparently doesn't support ACPI D3_hot, > so acpi_pm_device_sleep_state() returns D2 as the target state, where it > would return D3(cold) before the commit in question. > > To fix the regression, we'd need to reverse the current initial value of > the d3cold_allowed flag so that it is set to "true" by default and only > set to "false" for devices where we suspect there may be problems with > D3_cold (like PCI Express ports). Good. May I also request a few lines describing d3cold_allowed in e.g Documentation/ABI/testing/sysfs-bus-pci? I must admit that I thought that was the policy for any new sysfs file, but it seems that is only in the USB subsystem? Anyway, I believe it ought to be a requirement. If we are meant to tweak some knob, then we must known how and when to do so. If not, then why add it in the first place? Bjørn