1 files changed, 22 insertions, 0 deletions

diff --git a/drivers/acpi/processor_perflib.c b/drivers/acpi/processor_perflib.c
index 85b32376dad7..0af48a8554cd 100644
--- a/drivers/acpi/processor_perflib.c
+++ b/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;