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Diffstat (limited to 'Documentation/admin-guide/pm/intel_idle.rst')
| -rw-r--r-- | Documentation/admin-guide/pm/intel_idle.rst | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/Documentation/admin-guide/pm/intel_idle.rst b/Documentation/admin-guide/pm/intel_idle.rst index 8998598746a4..89309e1b0e48 100644 --- a/Documentation/admin-guide/pm/intel_idle.rst +++ b/Documentation/admin-guide/pm/intel_idle.rst @@ -168,7 +168,7 @@ and ``idle=nomwait``. If any of them is present in the kernel command line, the ``MWAIT`` instruction is not allowed to be used, so the initialization of ``intel_idle`` will fail. -Apart from that there are three module parameters recognized by ``intel_idle`` +Apart from that there are four module parameters recognized by ``intel_idle`` itself that can be set via the kernel command line (they cannot be updated via sysfs, so that is the only way to change their values). @@ -195,6 +195,23 @@ driver ignore the system's ACPI tables entirely or use them for all of the recognized processor models, respectively (they both are unset by default and ``use_acpi`` has no effect if ``no_acpi`` is set). +The value of the ``states_off`` module parameter (0 by default) represents a +list of idle states to be disabled by default in the form of a bitmask. + +Namely, the positions of the bits that are set in the ``states_off`` value are +the indices of idle states to be disabled by default (as reflected by the names +of the corresponding idle state directories in ``sysfs``, :file:`state0`, +:file:`state1` ... :file:`state<i>` ..., where ``<i>`` is the index of the given +idle state; see :ref:`idle-states-representation` in :doc:`cpuidle`). + +For example, if ``states_off`` is equal to 3, the driver will disable idle +states 0 and 1 by default, and if it is equal to 8, idle state 3 will be +disabled by default and so on (bit positions beyond the maximum idle state index +are ignored). + +The idle states disabled this way can be enabled (on a per-CPU basis) from user +space via ``sysfs``. + .. _intel-idle-core-and-package-idle-states: |