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Diffstat (limited to 'Documentation/admin-guide/thunderbolt.rst')
| -rw-r--r-- | Documentation/admin-guide/thunderbolt.rst | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/Documentation/admin-guide/thunderbolt.rst b/Documentation/admin-guide/thunderbolt.rst index 6a4cd1f159ca..dadcd66ee12f 100644 --- a/Documentation/admin-guide/thunderbolt.rst +++ b/Documentation/admin-guide/thunderbolt.rst @@ -197,3 +197,18 @@ information is missing. To recover from this mode, one needs to flash a valid NVM image to the host host controller in the same way it is done in the previous chapter. + +Forcing power +------------- +Many OEMs include a method that can be used to force the power of a +thunderbolt controller to an "On" state even if nothing is connected. +If supported by your machine this will be exposed by the WMI bus with +a sysfs attribute called "force_power". + +For example the intel-wmi-thunderbolt driver exposes this attribute in: + /sys/devices/platform/PNP0C14:00/wmi_bus/wmi_bus-PNP0C14:00/86CCFD48-205E-4A77-9C48-2021CBEDE341/force_power + + To force the power to on, write 1 to this attribute file. + To disable force power, write 0 to this attribute file. + +Note: it's currently not possible to query the force power state of a platform. |