The available tracepoint, pcie_ltssm_state_transition, monitors the LTSSM state transistion for debugging purpose. Add description about it.
Signed-off-by: Shawn Lin <[email protected]> --- Changes in v2: None Documentation/trace/events-pci-conotroller.rst | 41 ++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 Documentation/trace/events-pci-conotroller.rst diff --git a/Documentation/trace/events-pci-conotroller.rst b/Documentation/trace/events-pci-conotroller.rst new file mode 100644 index 0000000..8253d00 --- /dev/null +++ b/Documentation/trace/events-pci-conotroller.rst @@ -0,0 +1,41 @@ +.. 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: +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 root port name +* ``state`` - PCIe LTSSM state +* ``rate`` - PCIe bus speed + +**Example Usage**: + + # Enable the tracepoint + echo 1 > /sys/kernel/debug/tracing/events/pci/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 -- 2.7.4
