From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <5366451E.1050800@redhat.com> Date: Sun, 04 May 2014 16:48:14 +0300 From: Ronen Hod MIME-Version: 1.0 To: Marcel Apfelbaum , linux-pci@vger.kernel.org CC: linux-kernel@vger.kernel.org, bhelgaas@google.com, matthew@wil.cx, mst@redhat.com Subject: Re: [PATCH] PCI/shpchp: fix a bus speed issue on hotplug References: <1398954948-24219-1-git-send-email-marcel.a@redhat.com> In-Reply-To: <1398954948-24219-1-git-send-email-marcel.a@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-kernel-owner@vger.kernel.org List-ID: On 05/01/2014 05:35 PM, 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). Since the speed is irrelevant when running in a VM, I suggest that you either ignore it altogether, or "normalize" the speed of all the devices/bridges/buses in QEMU in order to avoid any conflicts in the first place. Thanks, Ronen. > > 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 > --- > 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))