From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH][tentative] PCI / ACPI: Rework PCI host bridge removal to avoid sysfs warnings Date: Mon, 06 Jan 2014 21:41:46 +0100 Message-ID: <4679785.iPCX7mECEL@vostro.rjw.lan> References: <37552283.kG1L4S8Daa@vostro.rjw.lan> <2459491.HIKjAnF27k@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7Bit Return-path: Received: from v094114.home.net.pl ([79.96.170.134]:57336 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753702AbaAFU17 (ORCPT ); Mon, 6 Jan 2014 15:27:59 -0500 In-Reply-To: Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Yinghai Lu Cc: Bjorn Helgaas , Greg Kroah-Hartman , Linux PCI , ACPI Devel Maling List , LKML , Yasuaki Ishimatsu , Tejun Heo On Monday, January 06, 2014 11:28:43 AM Yinghai Lu wrote: > On Thu, Jan 2, 2014 at 4:45 PM, Rafael J. Wysocki wrote: > > On Thursday, January 02, 2014 02:47:04 PM Yinghai Lu wrote: > >> > >> No. It should be before removing all root bus devices. > >> as they need to access the pci devices during stop ioapic and dmar. > >> > >> Also ioapic itself could one one pci device. > > > > Well, if we stop drivers first, then stop ioapic/dmar and *then* remove > > devices, it is possible to rebind a driver to a device after ioapic/dmar has > > been stopped, which I guess will not lead to anything nice? > > Not sure how that could happen. > > If it would really happen, we could set dev->match_driver to 0 in pci_stop_dev. Simply, run "modprobe -r driver && modprobe driver" in a loop and remove the PCI host bridge the given device is on in parallel to that. Chances are, you'll see some nice breakage. Also what happens if somebody uses the "remove" sysfs attribute on a device needed by ioapic/dmar? Rafael