From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ig0-f173.google.com ([209.85.213.173]:57084 "EHLO mail-ig0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753732AbaEOSlo (ORCPT ); Thu, 15 May 2014 14:41:44 -0400 Received: by mail-ig0-f173.google.com with SMTP id hn18so8298256igb.12 for ; Thu, 15 May 2014 11:41:44 -0700 (PDT) Date: Thu, 15 May 2014 12:41:46 -0600 From: Bjorn Helgaas To: Marcel Apfelbaum Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, matthew@wil.cx, mst@redhat.com Subject: Re: [PATCH] PCI/shpchp: fix a bus speed issue on hotplug Message-ID: <20140515184146.GA14506@google.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 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. 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))