• Myron Stowe's avatar
    PCI: pciehp: Clear Data Link Layer State Changed during init · 0d25d35c
    Myron Stowe authored
    During PCIe hot-plug initialization - pciehp_probe() - data structures
    related to slot capabilities are set up.  As part of this set up, ISRs are
    put in place to handle slot events and all event bits are cleared out.
    
    This patch adds the Data Link Layer State Changed (PCI_EXP_SLTSTA_DLLSC)
    Slot Status bit to the event bits that are cleared out during
    initialization.
    
    If the BIOS doesn't clear DLLSC before handoff to the OS, pciehp notices
    that it's set and interprets it as a new Link Up event, which results in
    spurious messages:
    
      pciehp 0000:82:04.0:pcie24: slot(4): Link Up event
      pciehp 0000:82:04.0:pcie24: Device 0000:83:00.0 already exists at 0000:83:00, cannot hot-add
      pciehp 0000:82:04.0:pcie24: Cannot add device at 0000:83:00
    
    Prior to e48f1b67 ("PCI: pciehp: Use link change notifications for
    hot-plug and removal"), pciehp ignored DLLSC.
    
    Reference:
      PCI-SIG.  PCI Express Base Specification Revision 4.0 Version 0.3
      (PCI-SIG, 2014): 7.8.11. Slot Status Register (Offset 1Ah).
    
    [bhelgaas: add e48f1b67 ref and stable tag]
    Fixes: e48f1b67 ("PCI: pciehp: Use link change notifications for hot-plug and removal")
    Link: https://bugzilla.kernel.org/show_bug.cgi?id=79611Signed-off-by: default avatarMyron Stowe <myron.stowe@redhat.com>
    Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
    CC: stable@vger.kernel.org	# v3.15+
    0d25d35c
pciehp_hpc.c 21.7 KB