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2078e1e7f7
e8303bb7a7("PCI/LINK: Report degraded links via link bandwidth notification") added dmesg logging whenever a link changes speed or width to a state that is considered degraded. Unfortunately, it cannot differentiate signal integrity-related link changes from those intentionally initiated by an endpoint driver, including drivers that may live in userspace or VMs when making use of vfio-pci. Some GPU drivers actively manage the link state to save power, which generates a stream of messages like this: vfio-pci 0000:07:00.0: 32.000 Gb/s available PCIe bandwidth, limited by 2.5 GT/s x16 link at 0000:00:02.0 (capable of 64.000 Gb/s with 5 GT/s x16 link) Since we can't distinguish the intentional changes from the signal integrity issues, leave the reporting turned off by default. Add a Kconfig option to turn it on if desired. Fixes:e8303bb7a7("PCI/LINK: Report degraded links via link bandwidth notification") Link: https://lore.kernel.org/linux-pci/20190501142942.26972-1-keith.busch@intel.com Signed-off-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
153 lines
4.1 KiB
Plaintext
153 lines
4.1 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0
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#
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# PCI Express Port Bus Configuration
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#
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config PCIEPORTBUS
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bool "PCI Express Port Bus support"
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depends on PCI
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help
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This enables PCI Express Port Bus support. Users can then enable
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support for Native Hot-Plug, Advanced Error Reporting, Power
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Management Events, and Downstream Port Containment.
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#
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# Include service Kconfig here
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#
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config HOTPLUG_PCI_PCIE
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bool "PCI Express Hotplug driver"
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depends on HOTPLUG_PCI && PCIEPORTBUS
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help
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Say Y here if you have a motherboard that supports PCI Express Native
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Hotplug
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When in doubt, say N.
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config PCIEAER
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bool "PCI Express Advanced Error Reporting support"
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depends on PCIEPORTBUS
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select RAS
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default y
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help
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This enables PCI Express Root Port Advanced Error Reporting
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(AER) driver support. Error reporting messages sent to Root
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Port will be handled by PCI Express AER driver.
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config PCIEAER_INJECT
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tristate "PCI Express error injection support"
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depends on PCIEAER
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help
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This enables PCI Express Root Port Advanced Error Reporting
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(AER) software error injector.
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Debugging AER code is quite difficult because it is hard
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to trigger various real hardware errors. Software-based
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error injection can fake almost all kinds of errors with the
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help of a user space helper tool aer-inject, which can be
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gotten from:
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http://www.kernel.org/pub/linux/utils/pci/aer-inject/
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#
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# PCI Express ECRC
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#
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config PCIE_ECRC
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bool "PCI Express ECRC settings control"
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depends on PCIEAER
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help
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Used to override firmware/bios settings for PCI Express ECRC
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(transaction layer end-to-end CRC checking).
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When in doubt, say N.
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#
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# PCI Express ASPM
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#
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config PCIEASPM
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bool "PCI Express ASPM control" if EXPERT
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depends on PCI && PCIEPORTBUS
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default y
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help
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This enables OS control over PCI Express ASPM (Active State
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Power Management) and Clock Power Management. ASPM supports
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state L0/L0s/L1.
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ASPM is initially set up by the firmware. With this option enabled,
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Linux can modify this state in order to disable ASPM on known-bad
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hardware or configurations and enable it when known-safe.
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ASPM can be disabled or enabled at runtime via
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/sys/module/pcie_aspm/parameters/policy
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When in doubt, say Y.
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config PCIEASPM_DEBUG
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bool "Debug PCI Express ASPM"
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depends on PCIEASPM
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help
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This enables PCI Express ASPM debug support. It will add per-device
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interface to control ASPM.
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choice
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prompt "Default ASPM policy"
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default PCIEASPM_DEFAULT
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depends on PCIEASPM
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config PCIEASPM_DEFAULT
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bool "BIOS default"
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depends on PCIEASPM
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help
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Use the BIOS defaults for PCI Express ASPM.
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config PCIEASPM_POWERSAVE
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bool "Powersave"
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depends on PCIEASPM
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help
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Enable PCI Express ASPM L0s and L1 where possible, even if the
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BIOS did not.
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config PCIEASPM_POWER_SUPERSAVE
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bool "Power Supersave"
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depends on PCIEASPM
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help
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Same as PCIEASPM_POWERSAVE, except it also enables L1 substates where
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possible. This would result in higher power savings while staying in L1
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where the components support it.
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config PCIEASPM_PERFORMANCE
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bool "Performance"
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depends on PCIEASPM
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help
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Disable PCI Express ASPM L0s and L1, even if the BIOS enabled them.
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endchoice
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config PCIE_PME
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def_bool y
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depends on PCIEPORTBUS && PM
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config PCIE_DPC
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bool "PCI Express Downstream Port Containment support"
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depends on PCIEPORTBUS && PCIEAER
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help
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This enables PCI Express Downstream Port Containment (DPC)
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driver support. DPC events from Root and Downstream ports
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will be handled by the DPC driver. If your system doesn't
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have this capability or you do not want to use this feature,
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it is safe to answer N.
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config PCIE_PTM
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bool "PCI Express Precision Time Measurement support"
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depends on PCIEPORTBUS
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help
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This enables PCI Express Precision Time Measurement (PTM)
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support.
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This is only useful if you have devices that support PTM, but it
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is safe to enable even if you don't.
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config PCIE_BW
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bool "PCI Express Bandwidth Change Notification"
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depends on PCIEPORTBUS
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help
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This enables PCI Express Bandwidth Change Notification. If
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you know link width or rate changes occur only to correct
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unreliable links, you may answer Y.
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