2 files changed, 14 insertions, 1 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 5fdf714f40a0..d006bb22f3ca 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1446,6 +1446,15 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                        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.
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 1405b393c93d..0e841eecb743 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -948,6 +948,7 @@ static struct cpufreq_driver intel_pstate_driver = {
 
 static int __initdata no_load;
 static int __initdata no_hwp;
+static unsigned int force_load;
 
 static int intel_pstate_msrs_not_valid(void)
 {
@@ -1094,7 +1095,8 @@ static bool intel_pstate_platform_pwr_mgmt_exists(void)
                         case PSS:
                                 return intel_pstate_no_acpi_pss();
                         case PPC:
-                                return intel_pstate_has_acpi_ppc();
+                                return intel_pstate_has_acpi_ppc() &&
+                                        (!force_load);
                         }
         }
 
@@ -1175,6 +1177,8 @@ static int __init intel_pstate_setup(char *str)
                 no_load = 1;
         if (!strcmp(str, "no_hwp"))
                 no_hwp = 1;
+        if (!strcmp(str, "force"))
+                force_load = 1;
         return 0;
 }
 early_param("intel_pstate", intel_pstate_setup);