From 2f124592c9b694907081d0ae7cf45bc5172eacdc Mon Sep 17 00:00:00 2001
From: Andi Kleen <ak@linux.intel.com>
Date: Thu, 26 Jan 2012 00:09:08 +0100
Subject: [PATCH] --- yaml --- r: 288850 b: refs/heads/master c:
 9061e0e16700ef228837e96987ff51794c956197 h: refs/heads/master v: v3

---
 [refs]                                 |  2 +-
 trunk/drivers/acpi/processor_driver.c  |  1 +
 trunk/drivers/acpi/processor_perflib.c | 22 ++++++++++++++++++++++
 trunk/include/acpi/processor.h         |  1 +
 4 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index 4138568e2fb4..0f84defb6812 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: b66b8b9a4a79087dde1b358a016e5c8739ccf186
+refs/heads/master: 9061e0e16700ef228837e96987ff51794c956197
diff --git a/trunk/drivers/acpi/processor_driver.c b/trunk/drivers/acpi/processor_driver.c
index 0034ede38710..e6920d0aca53 100644
--- a/trunk/drivers/acpi/processor_driver.c
+++ b/trunk/drivers/acpi/processor_driver.c
@@ -497,6 +497,7 @@ static int __cpuinit acpi_processor_add(struct acpi_device *device)
 
 #ifdef CONFIG_CPU_FREQ
 	acpi_processor_ppc_has_changed(pr, 0);
+	acpi_processor_load_module(pr);
 #endif
 	acpi_processor_get_throttling_info(pr);
 	acpi_processor_get_limit_info(pr);
diff --git a/trunk/drivers/acpi/processor_perflib.c b/trunk/drivers/acpi/processor_perflib.c
index 85b32376dad7..0af48a8554cd 100644
--- a/trunk/drivers/acpi/processor_perflib.c
+++ b/trunk/drivers/acpi/processor_perflib.c
@@ -240,6 +240,28 @@ void acpi_processor_ppc_exit(void)
 	acpi_processor_ppc_status &= ~PPC_REGISTERED;
 }
 
+/*
+ * Do a quick check if the systems looks like it should use ACPI
+ * cpufreq. We look at a _PCT method being available, but don't
+ * do a whole lot of sanity checks.
+ */
+void acpi_processor_load_module(struct acpi_processor *pr)
+{
+	static int requested;
+	acpi_status status = 0;
+	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+
+	if (!arch_has_acpi_pdc() || requested)
+		return;
+	status = acpi_evaluate_object(pr->handle, "_PCT", NULL, &buffer);
+	if (!ACPI_FAILURE(status)) {
+		printk(KERN_INFO PREFIX "Requesting acpi_cpufreq\n");
+		request_module_nowait("acpi_cpufreq");
+		requested = 1;
+	}
+	kfree(buffer.pointer);
+}
+
 static int acpi_processor_get_performance_control(struct acpi_processor *pr)
 {
 	int result = 0;
diff --git a/trunk/include/acpi/processor.h b/trunk/include/acpi/processor.h
index 610f6fb1bbc2..da57fdcc57d2 100644
--- a/trunk/include/acpi/processor.h
+++ b/trunk/include/acpi/processor.h
@@ -224,6 +224,7 @@ struct acpi_processor_errata {
 	} piix4;
 };
 
+extern void acpi_processor_load_module(struct acpi_processor *pr);
 extern int acpi_processor_preregister_performance(struct
 						  acpi_processor_performance
 						  __percpu *performance);