From 6be264986152c498562f26b15ed73c70aa37ce48 Mon Sep 17 00:00:00 2001
From: Dirk Brandewie <dirk.brandewie@gmail.com>
Date: Fri, 15 Feb 2013 22:55:10 +0100
Subject: [PATCH] cpufreq / intel_pstate: Add kernel command line option
disable intel_pstate.
When intel_pstate is configured into the kernel it will become the
preferred scaling driver for processors that it supports. Allow the
user to override this by adding:
intel_pstate=disable
on the kernel command line.
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
Documentation/kernel-parameters.txt | 5 +++++
drivers/cpufreq/intel_pstate.c | 16 ++++++++++++++++
2 files changed, 21 insertions(+)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 363e348bff9b9..b335c456feb97 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1131,6 +1131,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
0 disables intel_idle and fall back on acpi_idle.
1 to 6 specify maximum depth of C-state.
+ intel_pstate= [X86]
+ disable
+ Do not enable intel_pstate as the default
+ scaling driver for the supported processors
+
intremap= [X86-64, Intel-IOMMU]
on enable Interrupt Remapping (default)
off disable Interrupt Remapping
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index e87996355da0f..096fde0ebcb5b 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -773,11 +773,16 @@ static void intel_pstate_exit(void)
}
module_exit(intel_pstate_exit);
+static int __initdata no_load;
+
static int __init intel_pstate_init(void)
{
int rc = 0;
const struct x86_cpu_id *id;
+ if (no_load)
+ return -ENODEV;
+
id = x86_match_cpu(intel_pstate_cpu_ids);
if (!id)
return -ENODEV;
@@ -802,6 +807,17 @@ static int __init intel_pstate_init(void)
}
device_initcall(intel_pstate_init);
+static int __init intel_pstate_setup(char *str)
+{
+ if (!str)
+ return -EINVAL;
+
+ if (!strcmp(str, "disable"))
+ no_load = 1;
+ return 0;
+}
+early_param("intel_pstate", intel_pstate_setup);
+
MODULE_AUTHOR("Dirk Brandewie <dirk.j.brandewie@intel.com>");
MODULE_DESCRIPTION("'intel_pstate' - P state driver Intel Core processors");
MODULE_LICENSE("GPL");
--
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