intel_pstate: add kernel parameter to force loading
To force loading on Oracle Sun X86 servers, provide one kernel command line
parameter
intel_pstate = force
For those who are aware of the risk of no power capping capabily working
and try to get better performance with this driver.
Signed-off-by: Ethan Zhao <ethan.zhao@oracle.com>
Tested-by: Alexey Kodanev <alexey.kodanev@oracle.com>
Reviewed-by: Linda Knippers <linda.knippers@hp.com>
Acked-by: Kristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 5fdf714..d006bb2 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1446,6 +1446,15 @@
disable
Do not enable intel_pstate as the default
scaling driver for the supported processors
+ force
+ Enable intel_pstate on systems that prohibit it by default
+ in favor of acpi-cpufreq. Forcing the intel_pstate driver
+ instead of acpi-cpufreq may disable platform features, such
+ as thermal controls and power capping, that rely on ACPI
+ P-States information being indicated to OSPM and therefore
+ should be used with caution. This option does not work with
+ processors that aren't supported by the intel_pstate driver
+ or on platforms that use pcc-cpufreq instead of acpi-cpufreq.
no_hwp
Do not enable hardware P state control (HWP)
if available.