| Message ID | 1473316048-7598-1-git-send-email-sasha.neftin@intel.com |
|---|---|
| State | Changes Requested |
| Delegated to: | Jeff Kirsher |
| Headers | show |
> From: Intel-wired-lan [mailto:intel-wired-lan-bounces@lists.osuosl.org] On > Behalf Of Sasha Neftin > Sent: Wednesday, September 7, 2016 11:27 PM > To: intel-wired-lan@lists.osuosl.org > Subject: [Intel-wired-lan] [PATCH] PCI: disable FLR for 82579 device > > 82579 has a problem reattaching itself after the device is detached. > The bug was reported by Redhat. The suggested fix is to disable > FLR capability in PCIe configuration space. > > Reproduction: > Attach the device to a VM, then detach and try to attach again. > > Fix: > Disable FLR capability to prevent the 82579 from hanging. > > Signed-off-by: Sasha Neftin <sasha.neftin@intel.com> > --- > drivers/pci/quirks.c | 21 +++++++++++++++++++++ > 1 file changed, 21 insertions(+) Tested-by: Aaron Brown <aaron.f.brown@intel.com>
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index 37ff015..729ca69 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -4428,3 +4428,24 @@ static void quirk_intel_qat_vf_cap(struct pci_dev *pdev) } } DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x443, quirk_intel_qat_vf_cap); +/* + * Workaround FLR issues for 82579 + * This code disables the FLR (Function Level Reset) via PCIe, in order + * to workaround a bug found while using device passthrough, where the + * interface would become non-responsive. + * NOTE: the FLR bit is Read/Write Once (RWO) in config space, so if + * the BIOS or kernel writes this register * then this workaround will + * not work. + */ +static void quirk_intel_flr_cap_dis(struct pci_dev *dev) +{ + int pos = pci_find_capability(dev, PCI_CAP_ID_AF); + if (pos) { + u8 cap; + pci_read_config_byte(dev, pos + PCI_AF_CAP, &cap); + cap = cap & (~PCI_AF_CAP_FLR); + pci_write_config_byte(dev, pos + PCI_AF_CAP, cap); + } +} +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x1502, quirk_intel_flr_cap_dis); +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x1503, quirk_intel_flr_cap_dis);
82579 has a problem reattaching itself after the device is detached. The bug was reported by Redhat. The suggested fix is to disable FLR capability in PCIe configuration space. Reproduction: Attach the device to a VM, then detach and try to attach again. Fix: Disable FLR capability to prevent the 82579 from hanging. Signed-off-by: Sasha Neftin <sasha.neftin@intel.com> --- drivers/pci/quirks.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+)