Documentation/gpu/amdgpu/ptl.rst

Source file repositories/reference/linux-study-clean/Documentation/gpu/amdgpu/ptl.rst

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Documentation/gpu/amdgpu/ptl.rst
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Support Tooling And Documentation
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Support Tooling And Documentation: documentation
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Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

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Peak Tops Limiter (PTL) sysfs Interface
=======================================

Overview
--------
The Peak Tops Limiter (PTL) sysfs interface enables users to control and
configure the PTL feature for each GPU individually.  All PTL-related
sysfs files are located under `/sys/class/drm/cardX/device/ptl/`, where
`X` is the GPU index.  Through these files, users can enable or disable
PTL, set preferred data formats, and query supported formats for each GPU.

PTL sysfs files
----------------
The following files are available under `/sys/class/drm/cardX/device/ptl/`:

- `ptl_enable`
- `ptl_format`
- `ptl_supported_formats`

PTL Enable/Disable
------------------
File: `ptl_enable`
Type: Read/Write (rw)

Read: Returns the current PTL status as a string: `enabled` if PTL
is active, or `disabled` if inactive.

Write:

- Write `1` or `enabled` to enable PTL
- Write `0` or `disabled` to disable PTL

Examples::

    # Query PTL status
    cat /sys/class/drm/card1/device/ptl/ptl_enable
    # Output: enabled

    # Enable PTL
    sudo bash -c "echo 1 > /sys/class/drm/card1/device/ptl/ptl_enable"

    # Disable PTL
    sudo bash -c "echo 0 > /sys/class/drm/card1/device/ptl/ptl_enable"

PTL Format (Preferred Data Formats)
-----------------------------------
File: `ptl_format`
Type: Read/Write (rw)

Read: Returns the two preferred formats, e.g. `I8,F32`.

Write: Accepts two formats separated by a comma, e.g. `I8,F32`.

- Both formats must be supported and different.
- If an invalid format is provided (not supported, or both formats are the
  same), the driver will return "write error: Invalid argument".

Examples::

    # Query PTL formats
    cat /sys/class/drm/card1/device/ptl/ptl_format
    # Output: I8,F32

    # Set PTL formats
    sudo bash -c "echo I8,F32 > /sys/class/drm/card1/device/ptl/ptl_format"

Supported Formats
-----------------
File: `ptl_supported_formats`

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