From: Len Brown <lenb@kernel.org>
To: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, Len Brown <len.brown@intel.com>
Subject: [PATCH] cpufreq: Add the "cpufreq.off=1" cmdline option
Date: Tue, 28 Feb 2017 16:44:16 -0500 [thread overview]
Message-ID: <5fd2c737538635f032e8cfa115c802145f0a9911.1488318151.git.len.brown@intel.com> (raw)
From: Len Brown <len.brown@intel.com>
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>
---
Documentation/admin-guide/kernel-parameters.txt | 3 +++
drivers/cpufreq/cpufreq.c | 1 +
2 files changed, 4 insertions(+)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index be7c0d9506b1..3988d2311f97 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -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
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index cc475eff90b3..1c90782e3e11 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -2543,4 +2543,5 @@ static int __init cpufreq_core_init(void)
return 0;
}
+module_param(off, int, 0444);
core_initcall(cpufreq_core_init);
--
2.11.0.161.g6610af872
reply other threads:[~2017-03-01 6:42 UTC|newest]
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