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-rw-r--r--drivers/acpi/processor_driver.c1
-rw-r--r--drivers/acpi/processor_perflib.c22
2 files changed, 23 insertions, 0 deletions
diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c
index 0034ede..e6920d0 100644
--- a/drivers/acpi/processor_driver.c
+++ b/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/drivers/acpi/processor_perflib.c b/drivers/acpi/processor_perflib.c
index 85b3237..0af48a8 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;
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