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* cpufreq: intel_pstate: Document the current behavior and user interfaceRafael J. Wysocki2017-05-141-281/+0
| | | | | | | | | | | Add a document describing the current behavior and user space interface of the intel_pstate driver in the RST format and drop the existing outdated intel_pstate.txt document. Also update admin-guide/pm/cpufreq.rst with proper RST references to the new intel_pstate.rst document. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: intel_pstate: Operation mode control from sysfsRafael J. Wysocki2017-02-041-0/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | Make it possible to change the operation mode of intel_pstate with the help of a new sysfs attribute called "status". There are three possible configurations that can be selected using this attribute: "off" - The driver is not in use at this time. "active" - The driver works as a P-state governor (default). "passive" - The driver works as a regular cpufreq one and collaborates with the generic cpufreq governors (it sets P-states as requested by those governors). [This is the same mode the driver can be started in by passing intel_pstate=passive in the kernel command line.] The current setting is returned by reads from this attribute. Writing one of the above strings to it changes the operation mode as indicated by that string, if possible. If HW-managed P-states (HWP) feature is enabled, it is not possible to change the driver's operation mode and attempts to write to this attribute will fail. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* Documentation: intel_pstate: Document HWP energy/performance hintsSrinivas Pandruvada2016-12-081-0/+24
| | | | | | | | | Updated documentation for the support of energy performance hint in the HWP mode. Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> [ rjw: Subject & changelog ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* Documentation: intel_pstate: Update per core limitsSrinivas Pandruvada2016-11-011-1/+20
| | | | | | | Document restriction on per core P-State control. Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* Documentation: intel_pstate: PID tuning is not always availableSrinivas Pandruvada2016-10-211-4/+5
| | | | | | | | PID tuning is not available when the get_target_pstate_use_cpu_load() is used to calculate target_state. So update the documentation. Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* Documentation: cpufreq: intel_pstate: fix typoFelipe Franciosi2016-02-181-1/+1
| | | | | | | This just swaps a colon for a quote in the intel_pstate documentation. Signed-off-by: Felipe Franciosi <felipe@nutanix.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* Documentation: cpufreq: intel_pstate: enhance documentationSrinivas Pandruvada2016-01-051-42/+199
| | | | | | | | | This is an attempt to make documentation more user friendly. Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Reviewed-by: Doug Smythies <dsmythies@telus.net> Reviewed-by: Chen, Yu C <yu.c.chen@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* Documentation, intel_pstate: Improve legacy mode internal governors descriptionPrarit Bhargava2015-06-051-10/+11
| | | | | | | | | | | | | | | | | | | | The current documentation is incomplete wrt the intel_pstate legacy internal governors. The confusion comes from the general cpufreq governors which also use the names performance and powersave. This patch better differentiates between the two sets of governors and gives an explanation of how the internal P-state governors behave differently from one another. Also fix two minor typos. Cc: Prarit Bhargava <prarit@redhat.com> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: Kristen Carlson Accardi <kristen@linux.intel.com> Cc: Dirk Brandewie <dirk.j.brandewie@intel.com> Cc: x86@kernel.org Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Prarit Bhargava <prarit@redhat.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* intel_pstate: Add num_pstates to sysfsKristen Carlson Accardi2015-01-301-0/+4
| | | | | | | | | Add a sysfs interface to display the total number of supported pstates. This value is independent of whether turbo has been enabled or disabled. Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* intel_pstate: expose turbo range to sysfsKristen Carlson Accardi2015-01-301-0/+4
| | | | | | | | | | This patch adds "turbo_pct" to the intel_pstate sysfs interface. turbo_pct will display the percentage of the total supported pstates that are in the turbo range. This value is independent of whether turbo has been disabled or not. Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* intel_pstate: Add support for HWPDirk Brandewie2014-11-121-12/+25
| | | | | | | | | | | | | | | | | | Add support of Hardware Managed Performance States (HWP) described in Volume 3 section 14.4 of the SDM. With HWP enbaled intel_pstate will no longer be responsible for selecting P states for the processor. intel_pstate will continue to register to the cpufreq core as the scaling driver for CPUs implementing HWP. In HWP mode intel_pstate provides three functions reporting frequency to the cpufreq core, support for the set_policy() interface from the core and maintaining the intel_pstate sysfs interface in /sys/devices/system/cpu/intel_pstate. User preferences expressed via the set_policy() interface or the sysfs interface are forwared to the CPU via the HWP MSR interface. Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* intel_pstate: Update documentation of {max,min}_perf_pct sysfs filesDirk Brandewie2014-07-071-2/+5
| | | | | | | | | Update documentation to make the interpretation of the values clearer Link: https://bugzilla.kernel.org/show_bug.cgi?id=64251 Cc: 3.13+ <stable@vger.kernel.org> # 3.13+ Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* Documentation / cpufreq: add intel-pstate.txtRamkumar Ramachandra2014-01-061-0/+40
The Intel P-state driver is currently undocumented. Add some documentation based on the cover-letter sent with the original series. Cc: Dirk Brandewie <dirk.brandewie@gmail.com> Acked-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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