diff options
author | Stephen Rothwell <sfr@canb.auug.org.au> | 2014-01-10 11:38:23 +1100 |
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committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2014-01-10 11:38:23 +1100 |
commit | a59f7c00b6129f2b534caecacf567c2b928c82ae (patch) | |
tree | e3235a237dbd1cc335539f6434a043373e79c1be /Documentation | |
parent | a8e4c805c5c0c214a2b43a444db133cafbecff30 (diff) | |
parent | d0098103675c25e26961314b4446a1f3459d15fb (diff) |
Merge remote-tracking branch 'pm/linux-next'
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/ABI/testing/sysfs-devices-system-cpu | 24 | ||||
-rw-r--r-- | Documentation/acpi/namespace.txt | 9 | ||||
-rw-r--r-- | Documentation/cpu-freq/intel-pstate.txt | 40 |
3 files changed, 65 insertions, 8 deletions
diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index 468e4d48f884..d5a0d33c571f 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -200,3 +200,27 @@ Description: address and size of the percpu note. note of cpu#. crash_notes_size: size of the note of cpu#. + + +What: /sys/devices/system/cpu/intel_pstate/max_perf_pct + /sys/devices/system/cpu/intel_pstate/min_perf_pct + /sys/devices/system/cpu/intel_pstate/no_turbo +Date: February 2013 +Contact: linux-pm@vger.kernel.org +Description: Parameters for the Intel P-state driver + + Logic for selecting the current P-state in Intel + Sandybridge+ processors. The three knobs control + limits for the P-state that will be requested by the + driver. + + max_perf_pct: limits the maximum P state that will be requested by + the driver stated as a percentage of the available performance. + + min_perf_pct: limits the minimum P state that will be requested by + the driver stated as a percentage of the available performance. + + no_turbo: limits the driver to selecting P states below the turbo + frequency range. + + More details can be found in Documentation/cpu-freq/intel-pstate.txt diff --git a/Documentation/acpi/namespace.txt b/Documentation/acpi/namespace.txt index 260f6a3661fa..1860cb3865c6 100644 --- a/Documentation/acpi/namespace.txt +++ b/Documentation/acpi/namespace.txt @@ -235,10 +235,6 @@ Wysocki <rafael.j.wysocki@intel.com>. named object's type in the second column). In that case the object's directory in sysfs will contain the 'path' attribute whose value is the full path to the node from the namespace root. - struct acpi_device objects are created for the ACPI namespace nodes - whose _STA control methods return PRESENT or FUNCTIONING. The power - resource nodes or nodes without _STA are assumed to be both PRESENT - and FUNCTIONING. F: The struct acpi_device object is created for a fixed hardware feature (as indicated by the fixed feature flag's name in the second @@ -340,7 +336,7 @@ Wysocki <rafael.j.wysocki@intel.com>. | +-------------+-------+----------------+ | | | | +- - - - - - - +- - - - - - +- - - - - - - -+ - | +-| * PNP0C0D:00 | \_SB_.LID0 | acpi:PNP0C0D: | + | +-| PNP0C0D:00 | \_SB_.LID0 | acpi:PNP0C0D: | | | +- - - - - - - +- - - - - - +- - - - - - - -+ | | | | +------------+------------+-----------------------+ @@ -390,6 +386,3 @@ Wysocki <rafael.j.wysocki@intel.com>. attribute (as described earlier in this document). NOTE: N/A indicates the device object does not have the 'path' or the 'modalias' attribute. - NOTE: The PNP0C0D device listed above is highlighted (marked by "*") - to indicate it will be created only when its _STA methods return - PRESENT or FUNCTIONING. diff --git a/Documentation/cpu-freq/intel-pstate.txt b/Documentation/cpu-freq/intel-pstate.txt new file mode 100644 index 000000000000..e742d21dbd96 --- /dev/null +++ b/Documentation/cpu-freq/intel-pstate.txt @@ -0,0 +1,40 @@ +Intel P-state driver +-------------------- + +This driver implements a scaling driver with an internal governor for +Intel Core processors. The driver follows the same model as the +Transmeta scaling driver (longrun.c) and implements the setpolicy() +instead of target(). Scaling drivers that implement setpolicy() are +assumed to implement internal governors by the cpufreq core. All the +logic for selecting the current P state is contained within the +driver; no external governor is used by the cpufreq core. + +Intel SandyBridge+ processors are supported. + +New sysfs files for controlling P state selection have been added to +/sys/devices/system/cpu/intel_pstate/ + + max_perf_pct: limits the maximum P state that will be requested by + the driver stated as a percentage of the available performance. + + min_perf_pct: limits the minimum P state that will be requested by + the driver stated as a percentage of the available performance. + + no_turbo: limits the driver to selecting P states below the turbo + frequency range. + +For contemporary Intel processors, the frequency is controlled by the +processor itself and the P-states exposed to software are related to +performance levels. The idea that frequency can be set to a single +frequency is fiction for Intel Core processors. Even if the scaling +driver selects a single P state the actual frequency the processor +will run at is selected by the processor itself. + +New debugfs files have also been added to /sys/kernel/debug/pstate_snb/ + + deadband + d_gain_pct + i_gain_pct + p_gain_pct + sample_rate_ms + setpoint |