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author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2020-06-01 15:19:39 +0200 |
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committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2020-06-01 15:19:39 +0200 |
commit | ac7ccfc75faf2d82fe3176a100ed032621335b62 (patch) | |
tree | d33e01819b18a9c393a031fb487ad97aa86d45b2 /Documentation/admin-guide/pm | |
parent | f1ecbf79554d30baef4bef770b9500a1b7c51b82 (diff) | |
parent | 552abb884e97d26589964e5a8c7e736f852f95f0 (diff) | |
download | linux-stable-ac7ccfc75faf2d82fe3176a100ed032621335b62.tar.gz linux-stable-ac7ccfc75faf2d82fe3176a100ed032621335b62.tar.bz2 linux-stable-ac7ccfc75faf2d82fe3176a100ed032621335b62.zip |
Merge branch 'pm-cpufreq'
* pm-cpufreq:
cpufreq: Fix up cpufreq_boost_set_sw()
cpufreq: fix minor typo in struct cpufreq_driver doc comment
cpufreq: qoriq: Add platform dependencies
clk: qoriq: add cpufreq platform device
cpufreq: qoriq: convert to a platform driver
cpufreq: qcom: fix wrong compatible binding
cpufreq: imx-cpufreq-dt: support i.MX7ULP
cpufreq: dt: Add support for r8a7742
cpufreq: Add i.MX7ULP to cpufreq-dt-platdev blacklist
cpufreq: omap: Build driver by default for ARCH_OMAP2PLUS
cpufreq: intel_pstate: Use passive mode by default without HWP
Diffstat (limited to 'Documentation/admin-guide/pm')
-rw-r--r-- | Documentation/admin-guide/pm/intel_pstate.rst | 32 |
1 files changed, 19 insertions, 13 deletions
diff --git a/Documentation/admin-guide/pm/intel_pstate.rst b/Documentation/admin-guide/pm/intel_pstate.rst index ad392f3aee06..39d80bc29ccd 100644 --- a/Documentation/admin-guide/pm/intel_pstate.rst +++ b/Documentation/admin-guide/pm/intel_pstate.rst @@ -62,9 +62,10 @@ on the capabilities of the processor. Active Mode ----------- -This is the default operation mode of ``intel_pstate``. If it works in this -mode, the ``scaling_driver`` policy attribute in ``sysfs`` for all ``CPUFreq`` -policies contains the string "intel_pstate". +This is the default operation mode of ``intel_pstate`` for processors with +hardware-managed P-states (HWP) support. If it works in this mode, the +``scaling_driver`` policy attribute in ``sysfs`` for all ``CPUFreq`` policies +contains the string "intel_pstate". In this mode the driver bypasses the scaling governors layer of ``CPUFreq`` and provides its own scaling algorithms for P-state selection. Those algorithms @@ -138,12 +139,13 @@ internal P-state selection logic to be less performance-focused. Active Mode Without HWP ~~~~~~~~~~~~~~~~~~~~~~~ -This is the default operation mode for processors that do not support the HWP -feature. It also is used by default with the ``intel_pstate=no_hwp`` argument -in the kernel command line. However, in this mode ``intel_pstate`` may refuse -to work with the given processor if it does not recognize it. [Note that -``intel_pstate`` will never refuse to work with any processor with the HWP -feature enabled.] +This operation mode is optional for processors that do not support the HWP +feature or when the ``intel_pstate=no_hwp`` argument is passed to the kernel in +the command line. The active mode is used in those cases if the +``intel_pstate=active`` argument is passed to the kernel in the command line. +In this mode ``intel_pstate`` may refuse to work with processors that are not +recognized by it. [Note that ``intel_pstate`` will never refuse to work with +any processor with the HWP feature enabled.] In this mode ``intel_pstate`` registers utilization update callbacks with the CPU scheduler in order to run a P-state selection algorithm, either @@ -188,10 +190,14 @@ is not set. Passive Mode ------------ -This mode is used if the ``intel_pstate=passive`` argument is passed to the -kernel in the command line (it implies the ``intel_pstate=no_hwp`` setting too). -Like in the active mode without HWP support, in this mode ``intel_pstate`` may -refuse to work with the given processor if it does not recognize it. +This is the default operation mode of ``intel_pstate`` for processors without +hardware-managed P-states (HWP) support. It is always used if the +``intel_pstate=passive`` argument is passed to the kernel in the command line +regardless of whether or not the given processor supports HWP. [Note that the +``intel_pstate=no_hwp`` setting implies ``intel_pstate=passive`` if it is used +without ``intel_pstate=active``.] Like in the active mode without HWP support, +in this mode ``intel_pstate`` may refuse to work with processors that are not +recognized by it. If the driver works in this mode, the ``scaling_driver`` policy attribute in ``sysfs`` for all ``CPUFreq`` policies contains the string "intel_cpufreq". |