diff options
| author | Tal Gilboa <talgi@mellanox.com> | 2018-03-30 08:56:47 -0500 |
|---|---|---|
| committer | Bjorn Helgaas <helgaas@kernel.org> | 2018-04-03 08:58:30 -0500 |
| commit | 9e506a7b51474241f0c900e53e85512780275c05 (patch) | |
| tree | 95063571274cdd55ff08841a6dcbbdc5c20bc045 /drivers/pci | |
| parent | 6db79a88c67e4679d9c1e4a3f05c6385e21f6e9a (diff) | |
PCI: Add pcie_print_link_status() to log link speed and whether it's limited
Add pcie_print_link_status(). This logs the current settings of the link
(speed, width, and total available bandwidth).
If the device is capable of more bandwidth but is limited by a slower
upstream link, we include information about the link that limits the
device's performance.
The user may be able to move the device to a different slot for better
performance.
This provides a unified method for all PCI devices to report status and
issues, instead of each device reporting in a different way, using
different code.
Signed-off-by: Tal Gilboa <talgi@mellanox.com>
[bhelgaas: changelog, reword log messages, print device capabilities when
not limited, print bandwidth in Gb/s]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'drivers/pci')
| -rw-r--r-- | drivers/pci/pci.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 91138cbeb853..e7a3917ed389 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -5289,6 +5289,38 @@ 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 + * @dev: PCI device to query + * + * 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. + */ +void pcie_print_link_status(struct pci_dev *dev) +{ + enum pcie_link_width width, width_cap; + enum pci_bus_speed speed, speed_cap; + struct pci_dev *limiting_dev = NULL; + u32 bw_avail, bw_cap; + + 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) + pci_info(dev, "%u.%03u Gb/s available bandwidth (%s x%d link)\n", + bw_cap / 1000, bw_cap % 1000, + PCIE_SPEED2STR(speed_cap), width_cap); + else + pci_info(dev, "%u.%03u Gb/s available 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, + limiting_dev ? pci_name(limiting_dev) : "<unknown>", + bw_cap / 1000, bw_cap % 1000, + PCIE_SPEED2STR(speed_cap), width_cap); +} +EXPORT_SYMBOL(pcie_print_link_status); + +/** * pci_select_bars - Make BAR mask from the type of resource * @dev: the PCI device for which BAR mask is made * @flags: resource type mask to be selected |