From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755396Ab3F1KFv (ORCPT ); Fri, 28 Jun 2013 06:05:51 -0400 Received: from mga01.intel.com ([192.55.52.88]:56641 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755101Ab3F1KFt (ORCPT ); Fri, 28 Jun 2013 06:05:49 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.87,958,1363158000"; d="scan'208";a="361938441" From: "Kirill A. Shutemov" To: Bjorn Helgaas Cc: Mika Westerberg , Greg Kroah-Hartman , "Rafael J. Wysocki" , Jesse Barnes , Yinghai Lu , "Ronciak, John" , "Penner, Miles J" , Bruce Allan , "Kirill A. Shutemov" , Heikki Krogerus , "linux-kernel@vger.kernel.org" , "linux-pci@vger.kernel.org" , "x86@kernel.org" In-Reply-To: References: <1372177330-28013-1-git-send-email-mika.westerberg@linux.intel.com> <1372177330-28013-2-git-send-email-mika.westerberg@linux.intel.com> Subject: Re: [PATCH 1/6] PCI: acpiphp: do not check for SLOT_ENABLED in enable_device() Content-Transfer-Encoding: 7bit Message-Id: <20130628095138.D5B7BE0090@blue.fi.intel.com> Date: Fri, 28 Jun 2013 12:51:38 +0300 (EEST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Bjorn Helgaas wrote: > On Tue, Jun 25, 2013 at 10:22 AM, Mika Westerberg > wrote: > > From: "Kirill A. Shutemov" > > > > With Thunderbolt you can chain devices: connect a new devices to plugged > > one. In this case the slot is already enabled, but we still want to look > > for new devices behind it. > > > > We're going to reuse enable_device() for rescan for new devices on the > > enabled slot. Let's push the check up by stack. > > > > Signed-off-by: Kirill A. Shutemov > > Signed-off-by: Mika Westerberg > > --- > > drivers/pci/hotplug/acpiphp_glue.c | 5 ++--- > > 1 file changed, 2 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c > > index 59df857..b983e29 100644 > > --- a/drivers/pci/hotplug/acpiphp_glue.c > > +++ b/drivers/pci/hotplug/acpiphp_glue.c > > @@ -688,9 +688,6 @@ static int __ref enable_device(struct acpiphp_slot *slot) > > int num, max, pass; > > LIST_HEAD(add_list); > > > > - if (slot->flags & SLOT_ENABLED) > > - goto err_exit; > > - > > list_for_each_entry(func, &slot->funcs, sibling) > > acpiphp_bus_add(func); > > > > @@ -1242,6 +1239,8 @@ int acpiphp_enable_slot(struct acpiphp_slot *slot) > > goto err_exit; > > > > if (get_slot_status(slot) == ACPI_STA_ALL) { > > + if (slot->flags & SLOT_ENABLED) > > + goto err_exit; > > Why do we check for SLOT_ENABLED at all? I think we're handling a Bus > Check notification, which means "re-enumerate on the device tree > starting from the notification point." It doesn't say anything about > skipping the re-enumeration if we find a device that's already > enabled. > > It seems like we ought to just re-enumerate all the way down in case a > device was added farther down in the tree (which is what it sounds > like Thunderbolt is doing). Currently (with patchset applied), we have two users of acpiphp_enable_slot(): - /sys/bus/pci/slots/*/power - ACPI_NOTIFY_BUS_CHECK in _handle_hotplug_event_func(). Both are not related to Thunderbolt. Although, I think remove the check is good idea, I prefer to keep it separate from Thunderbolt enabling patchset, since it will change sysfs ABI a bit and can potentially affect othe ACPI PCI hotplug implementations. -- Kirill A. Shutemov