From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:11417 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750703AbaEQSsd (ORCPT ); Sat, 17 May 2014 14:48:33 -0400 Date: Sat, 17 May 2014 21:47:20 +0300 From: "Michael S. Tsirkin" To: Bjorn Helgaas Cc: Marcel Apfelbaum , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, matthew@wil.cx Subject: Re: [PATCH] PCI/shpchp: fix a bus speed issue on hotplug Message-ID: <20140517184720.GE9363@redhat.com> References: <1398954948-24219-1-git-send-email-marcel.a@redhat.com> <20140515184146.GA14506@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20140515184146.GA14506@google.com> Sender: linux-pci-owner@vger.kernel.org List-ID: On Thu, May 15, 2014 at 12:41:46PM -0600, Bjorn Helgaas wrote: > 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 > > I think cpqphp has similar issues. But I can't test it and I don't know if > anybody even uses it any more, so I'm just going to leave it alone. > > I reworked the changelog because I got confused about the bridge, adapter, > board, and what was what. Let me know if the one below is inaccurate. It's accurate I think. I only wish someone reworked the actual shpchp code to avoid the confusing adapter/board terminology. > I'll include this for v3.15 since it's a regression fix. > > Thanks, > Bjorn > > commit be219b7f518a36f62d67f057e9d31ebe9674814f > Author: Marcel Apfelbaum > Date: Thu May 1 17:35:48 2014 +0300 > > PCI: shpchp: Check bridge's secondary (not primary) bus speed > > When a new device is added below a hotplug bridge, the bridge's secondary > bus speed and the device's bus speed must match. The shpchp driver > previously checked the bridge's *primary* bus speed, not the secondary bus > speed. > > This caused hot-add errors like: > > shpchp 0000:00:03.0: Speed of bus ff and adapter 0 mismatch > > Check the secondary bus speed instead. > > [bhelgaas: changelog] > Link: https://bugzilla.kernel.org/show_bug.cgi?id=75251 > Fixes: 3749c51ac6c1 ("PCI: Make current and maximum bus speeds part of the PCI core") > Signed-off-by: Marcel Apfelbaum > Signed-off-by: Bjorn Helgaas > Acked-by: Michael S. Tsirkin > CC: stable@vger.kernel.org # v2.6.34+ > > diff --git a/drivers/pci/hotplug/shpchp_ctrl.c b/drivers/pci/hotplug/shpchp_ctrl.c > index 58499277903a..6efc2ec5e4db 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))