• Prarit Bhargava's avatar
    PCI/MSI: Stop disabling MSI/MSI-X in pci_device_shutdown() · fda78d7a
    Prarit Bhargava authored
    The pci_bus_type .shutdown method, pci_device_shutdown(), is called from
    device_shutdown() in the kernel restart and shutdown paths.
    
    Previously, pci_device_shutdown() called pci_msi_shutdown() and
    pci_msix_shutdown().  This disables MSI and MSI-X, which causes the device
    to fall back to raising interrupts via INTx.  But the driver is still bound
    to the device, it doesn't know about this change, and it likely doesn't
    have an INTx handler, so these INTx interrupts cause "nobody cared"
    warnings like this:
    
      irq 16: nobody cared (try booting with the "irqpoll" option)
      CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.8.2-1.el7_UNSUPPORTED.x86_64 #1
      Hardware name: Hewlett-Packard HP Z820 Workstation/158B, BIOS J63 v03.90 06/
      ...
    
    The MSI disabling code was added by d52877c7 ("pci/irq: let
    pci_device_shutdown to call pci_msi_shutdown v2") because a driver left MSI
    enabled and kdump failed because the kexeced kernel wasn't prepared to
    receive the MSI interrupts.
    
    Subsequent commits 1851617c ("PCI/MSI: Disable MSI at enumeration even
    if kernel doesn't support MSI") and  e80e7edc ("PCI/MSI: Initialize MSI
    capability for all architectures") changed the kexeced kernel to disable
    all MSIs itself so it no longer depends on the crashed kernel to clean up
    after itself.
    
    Stop disabling MSI/MSI-X in pci_device_shutdown().  This resolves the
    "nobody cared" unhandled IRQ issue above.  It also allows PCI serial
    devices, which may rely on the MSI interrupts, to continue outputting
    messages during reboot/shutdown.
    
    [bhelgaas: changelog, drop pci_msi_shutdown() and pci_msix_shutdown() calls
    altogether]
    Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=187351Signed-off-by: default avatarPrarit Bhargava <prarit@redhat.com>
    Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
    CC: Alex Williamson <alex.williamson@redhat.com>
    CC: David Arcari <darcari@redhat.com>
    CC: Myron Stowe <mstowe@redhat.com>
    CC: Lukas Wunner <lukas@wunner.de>
    CC: Keith Busch <keith.busch@intel.com>
    CC: Mika Westerberg <mika.westerberg@linux.intel.com>
    fda78d7a
pci-driver.c 35.7 KB