Commit d82f2692 authored Feb 28, 2017 by Len Brown Committed by Rafael J. Wysocki Mar 06, 2017

cpufreq: Add the "cpufreq.off=1" cmdline option



Add the "cpufreq.off=1" cmdline option.

At boot-time, this allows a user to request CONFIG_CPU_FREQ=n
behavior from a kernel built with CONFIG_CPU_FREQ=y.

This is analogous to the existing "cpuidle.off=1" option
and CONFIG_CPU_IDLE=y

This capability is valuable when we need to debug end-user
issues in the BIOS or in Linux.  It is also convenient
for enabling comparisons, which may otherwise require a new kernel,
or help from BIOS SETUP, which may be buggy or unavailable.

Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

parent 64078299

Documentation/admin-guide/kernel-parameters.txt

+3 −0

Original line number	Diff line number	Diff line
		@@ -662,6 +662,9 @@
		cpuidle.off=1 [CPU_IDLE]
		disable the cpuidle sub-system

		cpufreq.off=1 [CPU_FREQ]
		disable the cpufreq sub-system

		cpu_init_udelay=N
		[X86] Delay for N microsec between assert and de-assert
		of APIC INIT to start processors. This delay occurs

drivers/cpufreq/cpufreq.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -2532,4 +2532,5 @@ static int __init cpufreq_core_init(void)

		return 0;
		}
		module_param(off, int, 0444);
		core_initcall(cpufreq_core_init);