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Commit d64c3b0b authored by Kristen Carlson Accardi's avatar Kristen Carlson Accardi Committed by Rafael J. Wysocki
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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: default avatarKristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 17ad13ba

Documentation/kernel-parameters.txt

+3 −0
Original line number Diff line number Diff line
@@ -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)

drivers/cpufreq/intel_pstate.c

+6 −0
Original line number Diff line number Diff line
@@ -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);