From: Len Brown on
From: Len Brown <len.brown(a)>

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(a)>
drivers/acpi/processor_driver.c | 11 ++++++-----
1 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c
index 5675d97..deefa85 100644
--- 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_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,
@@ -920,9 +921,10 @@ static int __init acpi_processor_init(void)
if (!acpi_processor_dir)
return -ENOMEM;
- 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",

result = acpi_bus_register_driver(&acpi_processor_driver);
if (result < 0)
@@ -941,7 +943,6 @@ static int __init acpi_processor_init(void)

remove_proc_entry(ACPI_PROCESSOR_CLASS, acpi_root_dir);

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