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| author | Alexandru Gagniuc <mr.nuke.me@gmail.com> | 2018-08-07 02:25:35 +0300 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2018-08-10 20:29:04 +0300 |
| commit | 2d1ce5ec2117d16047334a1aa4b62e0cfb5a0605 (patch) | |
| tree | 61d71cf43436d8929699cb9032daa7ae623e87d0 /drivers/pci/pci.c | |
| parent | aa667c6408d20a84c7637420bc3b7aa0abab59a2 (diff) | |
| download | linux-2d1ce5ec2117d16047334a1aa4b62e0cfb5a0605.tar.xz | |
PCI: Check for PCIe Link downtraining
When both ends of a PCIe Link are capable of a higher bandwidth than is
currently in use, the Link is said to be "downtrained". A downtrained Link
may indicate hardware or configuration problems in the system, but it's
hard to identify such Links from userspace.
Refactor pcie_print_link_status() so it continues to always print PCIe
bandwidth information, as several NIC drivers desire.
Add a new internal __pcie_print_link_status() to emit a message only when a
device's bandwidth is constrained by the fabric and call it from the PCI
core for all devices, which identifies all downtrained Links. It also
emits messages for a few cases that are technically not downtrained, such
as a x4 device in an open-ended x1 slot.
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
[bhelgaas: changelog, move __pcie_print_link_status() declaration to
drivers/pci/, rename pcie_check_upstream_link() to
pcie_report_downtraining()]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'drivers/pci/pci.c')
| -rw-r--r-- | drivers/pci/pci.c | 27 |
1 files changed, 20 insertions, 7 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 97acba712e4e..a84d341504a5 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -5264,14 +5264,16 @@ u32 pcie_bandwidth_capable(struct pci_dev *dev, enum pci_bus_speed *speed, } /** - * pcie_print_link_status - Report the PCI device's link speed and width + * __pcie_print_link_status - Report the PCI device's link speed and width * @dev: PCI device to query + * @verbose: Print info even when enough bandwidth is available * - * Report the available bandwidth at the device. If this is less than the - * device is capable of, report the device's maximum possible bandwidth and - * the upstream link that limits its performance to less than that. + * If the available bandwidth at the device is less than the device is + * capable of, report the device's maximum possible bandwidth and the + * upstream link that limits its performance. If @verbose, always print + * the available bandwidth, even if the device isn't constrained. */ -void pcie_print_link_status(struct pci_dev *dev) +void __pcie_print_link_status(struct pci_dev *dev, bool verbose) { enum pcie_link_width width, width_cap; enum pci_bus_speed speed, speed_cap; @@ -5281,11 +5283,11 @@ void pcie_print_link_status(struct pci_dev *dev) bw_cap = pcie_bandwidth_capable(dev, &speed_cap, &width_cap); bw_avail = pcie_bandwidth_available(dev, &limiting_dev, &speed, &width); - if (bw_avail >= bw_cap) + if (bw_avail >= bw_cap && verbose) pci_info(dev, "%u.%03u Gb/s available PCIe bandwidth (%s x%d link)\n", bw_cap / 1000, bw_cap % 1000, PCIE_SPEED2STR(speed_cap), width_cap); - else + else if (bw_avail < bw_cap) pci_info(dev, "%u.%03u Gb/s available PCIe bandwidth, limited by %s x%d link at %s (capable of %u.%03u Gb/s with %s x%d link)\n", bw_avail / 1000, bw_avail % 1000, PCIE_SPEED2STR(speed), width, @@ -5293,6 +5295,17 @@ void pcie_print_link_status(struct pci_dev *dev) bw_cap / 1000, bw_cap % 1000, PCIE_SPEED2STR(speed_cap), width_cap); } + +/** + * pcie_print_link_status - Report the PCI device's link speed and width + * @dev: PCI device to query + * + * Report the available bandwidth at the device. + */ +void pcie_print_link_status(struct pci_dev *dev) +{ + __pcie_print_link_status(dev, true); +} EXPORT_SYMBOL(pcie_print_link_status); /** |