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Diffstat (limited to 'Documentation/trace/events-pci-controller.rst')
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diff --git a/Documentation/trace/events-pci-controller.rst b/Documentation/trace/events-pci-controller.rst new file mode 100644 index 000000000..cb9f71592 --- /dev/null +++ b/Documentation/trace/events-pci-controller.rst @@ -0,0 +1,42 @@ +.. SPDX-License-Identifier: GPL-2.0 + +====================================== +Subsystem Trace Points: PCI Controller +====================================== + +Overview +======== +The PCI controller tracing system provides tracepoints to monitor controller +level information for debugging purpose. The events normally show up here: + + /sys/kernel/tracing/events/pci_controller + +Cf. include/trace/events/pci_controller.h for the events definitions. + +Available Tracepoints +===================== + +pcie_ltssm_state_transition +--------------------------- + +Monitors PCIe LTSSM state transition including state and rate information +:: + + pcie_ltssm_state_transition "dev: %s state: %s rate: %s\n" + +**Parameters**: + +* ``dev`` - PCIe controller instance +* ``state`` - PCIe LTSSM state +* ``rate`` - PCIe date rate + +**Example Usage**: + +.. code-block:: shell + + # Enable the tracepoint + echo 1 > /sys/kernel/debug/tracing/events/pci_controller/pcie_ltssm_state_transition/enable + + # Monitor events (the following output is generated when a device is linking) + cat /sys/kernel/debug/tracing/trace_pipe + kworker/0:0-9 [000] ..... 5.600221: pcie_ltssm_state_transition: dev: a40000000.pcie state: RCVRY_EQ2 rate: 8.0 GT/s |