On Tue, Jul 29, 2014 at 4:17 PM, Yijing Wang <wangyijing@xxxxxxxxxx> wrote: > Currently we don't update device's mps value when doing > pci device hot-add. The hot-added device's mps will be set > to default value (128B). But the upstream port device's mps > may be larger than 128B which was set by firmware during > system bootup. In this case the new added device may not > work normally. This issue was found in huawei 5885 server > and Dell R620 server. And if we run the platform with windows, > this problem is gone. This patch try to update the hot added > device mps equal to its parent mps, if device mpss < parent mps, > print warning. > > References: https://bugzilla.kernel.org/show_bug.cgi?id=60671 http://marc.info/?l=e1000-devel&m=134182518500774&w=2 The bug was reported by Joe.jin@xxxxxxxxxx. the related hardware is SUN FIRE X2270 M2, it is not a hotplug sever except SAS HDD, and the the issue is definitely a BIOS bug. not related to the hotplug code path. was fixed by BIOS. Thanks, Ethan > Reported-by: Keith Busch <keith.busch@xxxxxxxxx> > Reported-by: Jordan_Hargrave@xxxxxxxx > Reported-by: Yijing Wang <wangyijing@xxxxxxxxxx> > Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx> > Cc: Jon Mason <jdmason@xxxxxxxx> > --- > drivers/pci/probe.c | 39 +++++++++++++++++++++++++++++++++++++++ > 1 files changed, 39 insertions(+), 0 deletions(-) > > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index e3cf8a2..583ca52 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -1613,6 +1613,44 @@ static void pcie_write_mrrs(struct pci_dev *dev) > dev_err(&dev->dev, "MRRS was unable to be configured with a safe value. If problems are experienced, try running with pci=pcie_bus_safe\n"); > } > > +/** > + * pcie_bus_update_set - update device mps when device doing hot-add > + * @dev: PCI device to set > + * > + * After device hot add, mps will be set to default(128B), But the > + * upstream port device's mps may be larger than 128B which was set > + * by firmware during system bootup. Then we should update the device > + * mps to equal to its parent mps, Or the device can not work normally. > + */ > +static void pcie_bus_update_set(struct pci_dev *dev) > +{ > + int mps, p_mps, mpss; > + struct pci_dev *parent; > + > + if (!pci_is_pcie(dev) || !dev->bus->self > + || !dev->bus->self->is_hotplug_bridge) > + return; > + > + parent = dev->bus->self; > + mps = pcie_get_mps(dev); > + p_mps = pcie_get_mps(parent); > + > + if (mps >= p_mps) > + return; > + > + mpss = 128 << dev->pcie_mpss; > + if (mpss < p_mps) { > + dev_warn(&dev->dev, "MPSS %d smaller than upstream MPS %d\n" > + "If necessary, use \"pci=pcie_bus_safe\" boot parameter to avoid this problem\n", > + mpss, p_mps); > + return; > + } > + > + pcie_write_mps(dev, p_mps); > + dev_info(&dev->dev, "Max Payload Size set to %4d/%4d (was %4d)\n", > + pcie_get_mps(dev), 128 << dev->pcie_mpss, mps); > +} > + > static void pcie_bus_detect_mps(struct pci_dev *dev) > { > struct pci_dev *bridge = dev->bus->self; > @@ -1637,6 +1675,7 @@ static int pcie_bus_configure_set(struct pci_dev *dev, void *data) > return 0; > > if (pcie_bus_config == PCIE_BUS_TUNE_OFF) { > + pcie_bus_update_set(dev); > pcie_bus_detect_mps(dev); > return 0; > } > -- > 1.7.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
