diff options
| -rw-r--r-- | Documentation/admin-guide/pm/intel_pstate.rst | 32 | ||||
| -rw-r--r-- | drivers/cpufreq/intel_pstate.c | 3 |
2 files changed, 21 insertions, 14 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". diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index 4d3429b2058f..8e23a698ce04 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -2771,6 +2771,8 @@ static int __init intel_pstate_init(void) pr_info("Invalid MSRs\n"); return -ENODEV; } + /* Without HWP start in the passive mode. */ + default_driver = &intel_cpufreq; hwp_cpu_matched: /* @@ -2816,7 +2818,6 @@ static int __init intel_pstate_setup(char *str) if (!strcmp(str, "disable")) { no_load = 1; } else if (!strcmp(str, "passive")) { - pr_info("Passive mode enabled\n"); default_driver = &intel_cpufreq; no_hwp = 1; } |