There was a irq storm bug when testing "pci=nomsi" case, and the root cause is: 'nomsi' will disable MSI and let devices and root ports use legacy INTX inerrupt, and likely make several devices/ports share one interrupt. In the failure case, BIOS doesn't disable the PCIE hotplug interrupts, and actually asserts the command-complete interrupt. As MSI is disabled, ACPI initialization code will not enumerate root port's PCIE hotplug capability, and pciehp service driver wont' be enabled for the root port to handle that interrupt, later on when it is shared and enabled by other device driver like NVME or NIC, the "nobody care irq storm" happens. So disable the pcie hotplug CCIE/HPIE interrupt in early boot phase when MSI is not enbaled. Signed-off-by: Feng Tang <feng.tang@xxxxxxxxxxxxxxxxx> --- drivers/pci/probe.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index b6536ed599c3..10d72156da9a 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1664,6 +1664,15 @@ void set_pcie_hotplug_bridge(struct pci_dev *pdev) pcie_capability_read_dword(pdev, PCI_EXP_SLTCAP, ®32); if (reg32 & PCI_EXP_SLTCAP_HPC) pdev->is_hotplug_bridge = 1; + + /* + * When MSI is disabled, root port will use legacy INTX, and likely + * share INTX interrupt line with other devices like NIC/NVME. There + * was real world issue that the CCIE IRQ is asserted afer boot, but + * will not be handled well and cause IRQ storm. So disable it early. + */ + if (!pci_msi_enabled()) + pcie_disable_hp_interrupts_early(pdev); } static void set_pcie_thunderbolt(struct pci_dev *dev) -- 2.43.5
