From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:65239 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752633AbaEAPot (ORCPT ); Thu, 1 May 2014 11:44:49 -0400 Date: Thu, 1 May 2014 18:43:39 +0300 From: "Michael S. Tsirkin" To: Marcel Apfelbaum Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, bhelgaas@google.com, matthew@wil.cx Subject: Re: [PATCH] PCI/shpchp: fix a bus speed issue on hotplug Message-ID: <20140501154339.GC9180@redhat.com> References: <1398954948-24219-1-git-send-email-marcel.a@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1398954948-24219-1-git-send-email-marcel.a@redhat.com> Sender: linux-pci-owner@vger.kernel.org List-ID: On Thu, May 01, 2014 at 05:35:48PM +0300, Marcel Apfelbaum wrote: > When a board is added, the shpchp driver checks if there > is a mismatch between the bridge's adapter and the bus speed. > If there is, it sets the subordinate speed (if there is no device on it). > > However, it takes the reference of the board speed from the primary bus > and not from the subordinate. If the primary bus is PCI and not PCIX/PCIe, > its speed is not updated and remains 0xff. As a result hotplug fails > with error: "Speed of bus ff and adapter 0 mismatch". > > Fixed that by checking the speed against the subordinate bus. > > Signed-off-by: Marcel Apfelbaum > Acked-by: Michael S. Tsirkin Looking at git history, I suspect this is a regression introduced by commit 3749c51ac6c1560aa1cb1520066bed84c6f8152a Author: Matthew Wilcox Date: Sun Dec 13 08:11:32 2009 -0500 PCI: Make current and maximum bus speeds part of the PCI core At least I remember this configuration worked for me early in 2009... > --- > drivers/pci/hotplug/shpchp_ctrl.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/hotplug/shpchp_ctrl.c b/drivers/pci/hotplug/shpchp_ctrl.c > index 5849927..6efc2ec 100644 > --- a/drivers/pci/hotplug/shpchp_ctrl.c > +++ b/drivers/pci/hotplug/shpchp_ctrl.c > @@ -282,8 +282,8 @@ static int board_added(struct slot *p_slot) > return WRONG_BUS_FREQUENCY; > } > > - bsp = ctrl->pci_dev->bus->cur_bus_speed; > - msp = ctrl->pci_dev->bus->max_bus_speed; > + bsp = ctrl->pci_dev->subordinate->cur_bus_speed; > + msp = ctrl->pci_dev->subordinate->max_bus_speed; > > /* Check if there are other slots or devices on the same bus */ > if (!list_empty(&ctrl->pci_dev->subordinate->devices)) > -- > 1.8.3.1