From 5b0764cac9f1b70a6704b0e546be67c24cc05517 Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Fri, 16 Feb 2018 10:55:38 -0600 Subject: PCI: Probe for device reset support during enumeration Previously we called pci_probe_reset_function() in this path: pci_sysfs_init # late_initcall for_each_pci_dev(dev) pci_create_sysfs_dev_files(dev) pci_create_capabilities_sysfs(dev) pci_probe_reset_function pci_dev_specific_reset pcie_has_flr pcie_capability_read_dword pci_sysfs_init() is a late_initcall, and a driver may have already claimed one of these devices and enabled runtime power management for it, so the device could already be in D3 by the time we get to pci_sysfs_init(). The device itself should respond to the config read even while it's in D3hot, but if an upstream bridge is also in D3hot, the read won't even reach the device because the bridge won't forward it downstream to the device. If the bridge is a PCIe port, it should complete the read as an Unsupported Request, which may be reported to the CPU as an exception or as invalid data. Avoid this case by probing for reset support from pci_init_capabilities(), before a driver can claim the device. The device may be in D3hot, but any bridges leading to it should be in D0, so the device's config space should be fully accessible at that point. Signed-off-by: Bjorn Helgaas Reviewed-by: Rafael J. Wysocki --- drivers/pci/pci-sysfs.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'drivers/pci/pci-sysfs.c') diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index eb6bee8724cc..4933f0270471 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -1542,11 +1542,10 @@ static int pci_create_capabilities_sysfs(struct pci_dev *dev) /* Active State Power Management */ pcie_aspm_create_sysfs_dev_files(dev); - if (!pci_probe_reset_function(dev)) { + if (dev->reset_fn) { retval = device_create_file(&dev->dev, &reset_attr); if (retval) goto error; - dev->reset_fn = 1; } return 0; -- cgit v1.2.3-59-g8ed1b