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cpufreq: intel_pstate: Operation mode control from sysfs

Forráskód böngészése 
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>
This commit is contained in:
Rafael J. Wysocki
2017-01-05 02:53:12 +01:00
szülő 0c30b65b3c
commit fb1fe1041c
2 fájl változott, egészen pontosan 195 új sor hozzáadva és 44 régi sor törölve
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15
Documentation/cpu-freq/intel-pstate.txt
Fájl megtekintése

@@ -85,6 +85,21 @@ Sysfs will show :
Refer to "Intel® 64 and IA-32 Architectures Software Developer’s Manual
Volume 3: System Programming Guide" to understand ratios.
There is one more sysfs attribute in /sys/devices/system/cpu/intel_pstate/
that can be used for controlling the operation mode of the driver:
status: Three settings are possible:
"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).
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) are enabled, it is not
possible to change the driver's operation mode and attempts to write to
this attribute will fail.
cpufreq sysfs for Intel P-State
Since this driver registers with cpufreq, cpufreq sysfs is also presented.