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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2020-02-03 11:57:08 +0100
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2020-02-03 11:57:08 +0100
commit3a5be9b8f43346a24f31c0017cb2566a6b2c72c5 (patch)
tree346315651d61e9e5ee7e7263a76dff66e5346db8 /Documentation
parentcf3c8f84d1401fed5010784034d104cc689061d5 (diff)
intel_idle: Introduce 'use_acpi' module parameter
For diagnostics, it is generally useful to be able to make intel_idle take the system's ACPI tables into consideration even if that is not required for the processor model in there, so introduce a new module parameter, 'use_acpi', to make that happen and update the documentation to cover it. While at it, fix the 'no_acpi' module parameter name in the documentation. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/admin-guide/pm/intel_idle.rst13
1 files changed, 9 insertions, 4 deletions
diff --git a/Documentation/admin-guide/pm/intel_idle.rst b/Documentation/admin-guide/pm/intel_idle.rst
index afbf778035f8..8998598746a4 100644
--- a/Documentation/admin-guide/pm/intel_idle.rst
+++ b/Documentation/admin-guide/pm/intel_idle.rst
@@ -60,6 +60,9 @@ of the system. The former are always used if the processor model at hand is
recognized by ``intel_idle`` and the latter are used if that is required for
the given processor model (which is the case for all server processor models
recognized by ``intel_idle``) or if the processor model is not recognized.
+[There is a module parameter that can be used to make the driver use the ACPI
+tables with any processor model recognized by it; see
+`below <intel-idle-parameters_>`_.]
If the ACPI tables are going to be used for building the list of available idle
states, ``intel_idle`` first looks for a ``_CST`` object under one of the ACPI
@@ -165,7 +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 two module parameters recognized by ``intel_idle``
+Apart from that there are three 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).
@@ -186,9 +189,11 @@ QoS) feature can be used to prevent ``CPUIdle`` from touching those idle states
even if they have been enumerated (see :ref:`cpu-pm-qos` in :doc:`cpuidle`).
Setting ``max_cstate`` to 0 causes the ``intel_idle`` initialization to fail.
-The ``noacpi`` module parameter (which is recognized by ``intel_idle`` if the
-kernel has been configured with ACPI support), can be set to make the driver
-ignore the system's ACPI tables entirely (it is unset by default).
+The ``no_acpi`` and ``use_acpi`` module parameters (recognized by ``intel_idle``
+if the kernel has been configured with ACPI support) can be set to make the
+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).
.. _intel-idle-core-and-package-idle-states: