intel_pstate: provide option to only use intel_pstate with HWP

Allow users the option to disable the driver for any hardware
which does not support HWP.

Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Kristen Carlson Accardi 2015-02-06 13:41:55 -08:00 committed by Rafael J. Wysocki
parent 17ad13ba84
commit d64c3b0bb9
2 changed files with 9 additions and 0 deletions

View file

@ -1469,6 +1469,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
no_hwp
Do not enable hardware P state control (HWP)
if available.
hwp_only
Only load intel_pstate on systems which support
hardware P state control (HWP) if available.
intremap= [X86-64, Intel-IOMMU]
on enable Interrupt Remapping (default)

View file

@ -1019,6 +1019,7 @@ static struct cpufreq_driver intel_pstate_driver = {
static int __initdata no_load;
static int __initdata no_hwp;
static int __initdata hwp_only;
static unsigned int force_load;
static int intel_pstate_msrs_not_valid(void)
@ -1216,6 +1217,9 @@ static int __init intel_pstate_init(void)
if (cpu_has(c,X86_FEATURE_HWP) && !no_hwp)
intel_pstate_hwp_enable();
if (!hwp_active && hwp_only)
goto out;
rc = cpufreq_register_driver(&intel_pstate_driver);
if (rc)
goto out;
@ -1250,6 +1254,8 @@ static int __init intel_pstate_setup(char *str)
no_hwp = 1;
if (!strcmp(str, "force"))
force_load = 1;
if (!strcmp(str, "hwp_only"))
hwp_only = 1;
return 0;
}
early_param("intel_pstate", intel_pstate_setup);