powernow-k8: Cleanup module request

Check whether we've actually already loaded acpi-cpufreq before
requesting it.
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/powernow-k8.c

@@ -1249,6 +1249,24 @@ static struct cpufreq_driver cpufreq_amd64_driver = {
 	.attr		= powernow_k8_attr,
 };
 
+static void __request_acpi_cpufreq(void)
+{
+	const char *cur_drv, *drv = "acpi-cpufreq";
+
+	cur_drv = cpufreq_get_current_driver();
+	if (!cur_drv)
+		goto request;
+
+	if (strncmp(cur_drv, drv, min_t(size_t, strlen(cur_drv), strlen(drv))))
+		pr_warn(PFX "WTF driver: %s\n", cur_drv);
+
+	return;
+
+ request:
+	pr_warn(PFX "This CPU is not supported anymore, using acpi-cpufreq instead.\n");
+	request_module(drv);
+}
+
 /* driver entry point for init */
 static int __cpuinit powernowk8_init(void)
 {
@@ -1256,8 +1274,7 @@ static int __cpuinit powernowk8_init(void)
 	int rv;
 
 	if (static_cpu_has(X86_FEATURE_HW_PSTATE)) {
-		pr_warn(PFX "this CPU is not supported anymore, using acpi-cpufreq instead.\n");
-		request_module("acpi-cpufreq");
+		__request_acpi_cpufreq();
 		return -ENODEV;
 	}