From 0d25d35c987d7b0b63368d9c1ae35a917e1a7bab Mon Sep 17 00:00:00 2001 From: Myron Stowe Date: Tue, 17 Jun 2014 13:27:34 -0600 Subject: [PATCH] PCI: pciehp: Clear Data Link Layer State Changed during init 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 e48f1b67f668 ("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 e48f1b67f668 ref and stable tag] Fixes: e48f1b67f668 ("PCI: pciehp: Use link change notifications for hot-plug and removal") Link: https://bugzilla.kernel.org/show_bug.cgi?id=79611 Signed-off-by: Myron Stowe Signed-off-by: Bjorn Helgaas CC: stable@vger.kernel.org # v3.15+ --- drivers/pci/hotplug/pciehp_hpc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index f7c370993ab4..9da84b8b27d8 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -783,7 +783,7 @@ struct controller *pcie_init(struct pcie_device *dev) pcie_capability_write_word(pdev, PCI_EXP_SLTSTA, PCI_EXP_SLTSTA_ABP | PCI_EXP_SLTSTA_PFD | PCI_EXP_SLTSTA_MRLSC | PCI_EXP_SLTSTA_PDC | - PCI_EXP_SLTSTA_CC); + PCI_EXP_SLTSTA_CC | PCI_EXP_SLTSTA_DLLSC); /* Disable software notification */ pcie_disable_notification(ctrl);