ACPI: allow a native cpuidle driver to displace ACPI

The ACPI driver would fail probe when it found that
another driver had previously registered with cpuidle.

But this is a natural situation, as a native hardware
cpuidle driver should be able to bind instead of ACPI,
and the ACPI processor driver should be able to handle
yielding control of C-states while still handling
P-states and T-states.

Add a KERN_DEBUG line showing when acpi_idle
does successfully register.

Signed-off-by: Len Brown <len.brown@intel.com>

diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c
index 5675d97..deefa85 100644 (file)
--- a/drivers/acpi/processor_driver.c
+++ b/drivers/acpi/processor_driver.c
@@ -616,7 +616,8 @@ static int __cpuinit acpi_processor_add(struct acpi_device *device)
        acpi_processor_get_limit_info(pr);
 
 
-       acpi_processor_power_init(pr, device);
+       if (cpuidle_get_driver() == &acpi_idle_driver)
+               acpi_processor_power_init(pr, device);
 
        pr->cdev = thermal_cooling_device_register("Processor", device,
                                                &processor_cooling_ops);
@@ -920,9 +921,10 @@ static int __init acpi_processor_init(void)
        if (!acpi_processor_dir)
                return -ENOMEM;
 #endif
-       result = cpuidle_register_driver(&acpi_idle_driver);
-       if (result < 0)
-               goto out_proc;
+
+       if (!cpuidle_register_driver(&acpi_idle_driver))
+               printk(KERN_DEBUG "ACPI: %s registered with cpuidle\n",
+                       acpi_idle_driver.name);
 
        result = acpi_bus_register_driver(&acpi_processor_driver);
        if (result < 0)
@@ -941,7 +943,6 @@ static int __init acpi_processor_init(void)
 out_cpuidle:
        cpuidle_unregister_driver(&acpi_idle_driver);
 
-out_proc:
 #ifdef CONFIG_ACPI_PROCFS
        remove_proc_entry(ACPI_PROCESSOR_CLASS, acpi_root_dir);
 #endif