From: Rafael J. Wysocki Date: Mon, 21 Nov 2022 18:15:18 +0000 (+0100) Subject: PCI/portdrv: Set PCIE_PORT_SERVICE_HP for Root and Downstream Ports only X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=05f5747414c6ecb8a7f9b0c1dc10bcffa6dfb5ba;p=linux.git PCI/portdrv: Set PCIE_PORT_SERVICE_HP for Root and Downstream Ports only It is reported that on some systems pciehp binds to an Upstream Port and attempts to operate it which causes devices below the Port to disappear from the bus. This happens because acpiphp sets dev->is_hotplug_bridge for that Port (after receiving a Device Check notification on it from the platform firmware via ACPI) during the enumeration of PCI devices. get_port_device_capability() sees that dev->is_hotplug_bridge is set and adds PCIE_PORT_SERVICE_HP to Port services (which allows pciehp to bind to the Port in question) without consulting the PCIe type, which should be either Root Port or Downstream Port for the hotplug capability to be present. Per PCIe r6.0, sec 7.5.3.2, the Slot Implemented bit is only valid for Downstream Ports (including Root Ports), and PCIe hotplug depends on the Slot Capabilities / Control / Status registers. Make get_port_device_capability() more robust by adding a PCIe type check to it before adding PCIE_PORT_SERVICE_HP to Port services which helps to avoid the problem. [bhelgaas: add spec citation] Suggested-by: Lukas Wunner Link: https://lore.kernel.org/r/4786090.31r3eYUQgx@kreacher Reported-by: Rodrigo Vivi Signed-off-by: Rafael J. Wysocki Signed-off-by: Bjorn Helgaas Reviewed-by: Lukas Wunner --- diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c index 1ac7fec47d6fb..98f0126aaa903 100644 --- a/drivers/pci/pcie/portdrv_core.c +++ b/drivers/pci/pcie/portdrv_core.c @@ -209,6 +209,8 @@ static int get_port_device_capability(struct pci_dev *dev) int services = 0; if (dev->is_hotplug_bridge && + (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT || + pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM) && (pcie_ports_native || host->native_pcie_hotplug)) { services |= PCIE_PORT_SERVICE_HP;