[PATCH v2 2/3] Documentation: tracing: Add PCI controller event documentation

[Manivannan Sadhasivam]

On Fri, Jan 09, 2026 at 11:29:48AM +0800, Shawn Lin wrote:
> The available tracepoint, pcie_ltssm_state_transition, monitors the LTSSM state
> transistion for debugging purpose. Add description about it.
> 
> Signed-off-by: Shawn Lin <shawn.lin at rock-chips.com>
> ---
> 
> 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

'PCIe controller instance'

> +* ``state`` - PCIe LTSSM state
> +* ``rate`` - PCIe bus speed

'PCIe data rate'

> +
> +**Example Usage**:
> +
> +    # Enable the tracepoint
> +    echo 1 > /sys/kernel/debug/tracing/events/pci/pcie_ltssm_state_transition/enable

/sys/kernel/debug/tracing/events/pci_controller/pcie_ltssm_state_transition/enable

- Mani

-- 
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