[v6,2/7] ACPI: Make ACPI processor driver more extensible

Message ID 9e352cbe2feac01158a21511bac5c544dc2f29e2.1434398373.git.ashwin.chaugule@linaro.org
State New
Headers show

Commit Message

Ashwin Chaugule June 15, 2015, 8:09 p.m.
The ACPI processor driver is currently tied too closely
to the ACPI C-states (CST), P-states (PSS) and other related
constructs for controlling CPU idle and CPU performance.

The newer ACPI specification (v5.1 onwards) introduces
alternative methods to CST and PSS. These new mechanisms
are described within each ACPI Processor object and so they
need to be scanned whenever a new Processor object is detected.
This patch introduces two new Kconfig symbols to allow for
finer configurability among the various options for controlling
CPU idle and performance states. There is no change in functionality
and these options are defaulted to enabled to maintain previous
behaviour.

The following patchwork introduces CPPC: A newer method of
controlling CPU performance. The OS is not expected to support CPPC
and PSS at runtime. So the kconfig option lets us make these two
mutually exclusive at compile time.

Signed-off-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
Reviewed-by: Al Stone <al.stone@linaro.org>
---
 drivers/acpi/Kconfig            |  31 +++++++++--
 drivers/acpi/Makefile           |   7 ++-
 drivers/acpi/processor_driver.c |  86 ++++++++++++++++++----------
 drivers/cpufreq/Kconfig         |   2 +-
 drivers/cpufreq/Kconfig.x86     |   2 +
 include/acpi/processor.h        | 120 ++++++++++++++++++++++++++++------------
 6 files changed, 176 insertions(+), 72 deletions(-)

Comments

Ashwin Chaugule July 8, 2015, 1:27 a.m. | #1
On 7 July 2015 at 21:07, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> On Monday, June 15, 2015 04:09:06 PM Ashwin Chaugule wrote:
>> The ACPI processor driver is currently tied too closely
>> to the ACPI C-states (CST), P-states (PSS) and other related
>> constructs for controlling CPU idle and CPU performance.
>>
>> The newer ACPI specification (v5.1 onwards) introduces
>> alternative methods to CST and PSS. These new mechanisms
>> are described within each ACPI Processor object and so they
>> need to be scanned whenever a new Processor object is detected.
>> This patch introduces two new Kconfig symbols to allow for
>> finer configurability among the various options for controlling
>> CPU idle and performance states. There is no change in functionality
>> and these options are defaulted to enabled to maintain previous
>> behaviour.
>>
>> The following patchwork introduces CPPC: A newer method of
>> controlling CPU performance. The OS is not expected to support CPPC
>> and PSS at runtime. So the kconfig option lets us make these two
>> mutually exclusive at compile time.
>>
>> Signed-off-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
>> Reviewed-by: Al Stone <al.stone@linaro.org>
>> ---
>>  drivers/acpi/Kconfig            |  31 +++++++++--
>>  drivers/acpi/Makefile           |   7 ++-
>>  drivers/acpi/processor_driver.c |  86 ++++++++++++++++++----------
>>  drivers/cpufreq/Kconfig         |   2 +-
>>  drivers/cpufreq/Kconfig.x86     |   2 +
>>  include/acpi/processor.h        | 120 ++++++++++++++++++++++++++++------------
>>  6 files changed, 176 insertions(+), 72 deletions(-)
>>
>> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
>> index ab2cbb5..5942754 100644
>> --- a/drivers/acpi/Kconfig
>> +++ b/drivers/acpi/Kconfig
>> @@ -166,18 +166,39 @@ config ACPI_DOCK
>>         This driver supports ACPI-controlled docking stations and removable
>>         drive bays such as the IBM Ultrabay and the Dell Module Bay.
>>
>> -config ACPI_PROCESSOR
>> -     tristate "Processor"
>> -     select THERMAL
>> -     select CPU_IDLE
>> +config ACPI_CST
>> +     bool "ACPI C states (CST) driver"
>> +     depends on ACPI_PROCESSOR
>>       depends on X86 || IA64
>> +     select CPU_IDLE
>>       default y
>>       help
>>         This driver installs ACPI as the idle handler for Linux and uses
>>         ACPI C2 and C3 processor states to save power on systems that
>> -       support it.  It is required by several flavors of cpufreq
>> +       support it.
>> +
>> +config ACPI_PSS
>> +     bool "ACPI P States (PSS) driver"
>> +     depends on ACPI_PROCESSOR
>> +     depends on X86 || IA64
>> +     select THERMAL
>> +     default y
>> +     help
>> +       This driver implements ACPI methods for controlling CPU performance
>> +       using PSS methods as described in the ACPI spec. It also enables support
>> +       for ACPI based performance throttling (TSS) and ACPI based thermal
>> +       monitoring. It is required by several flavors of cpufreq
>>         performance-state drivers.
>
> For starters, I don't like these new Kconfig options.
>
> Isn't there a way to implement what you need without adding them?

We need to use the ACPI Processor driver for CPPC without including
all its current dependencies. (i.e. PSS, TSS, CSS etc.). The upcoming
LPI work from Sudeep will also face the same issue. I considered the
alternative of adding a probe routine which matches
ACPI_PROCESSOR_OBJECT/DEVICE_HID to each driver, but this seemed like
a better option. Do you have any other ideas?

Thanks,
Ashwin.
Ashwin Chaugule July 8, 2015, 1:42 p.m. | #2
Hello,

On 8 July 2015 at 09:34, Rafael J. Wysocki <rafael@kernel.org> wrote:
> Hi Ashwin,
>
> On Wed, Jul 8, 2015 at 3:27 AM, Ashwin Chaugule
> <ashwin.chaugule@linaro.org> wrote:
>> On 7 July 2015 at 21:07, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
>>> On Monday, June 15, 2015 04:09:06 PM Ashwin Chaugule wrote:
>>>> The ACPI processor driver is currently tied too closely
>>>> to the ACPI C-states (CST), P-states (PSS) and other related
>>>> constructs for controlling CPU idle and CPU performance.
>>>>
>>>> The newer ACPI specification (v5.1 onwards) introduces
>>>> alternative methods to CST and PSS. These new mechanisms
>>>> are described within each ACPI Processor object and so they
>>>> need to be scanned whenever a new Processor object is detected.
>>>> This patch introduces two new Kconfig symbols to allow for
>>>> finer configurability among the various options for controlling
>>>> CPU idle and performance states. There is no change in functionality
>>>> and these options are defaulted to enabled to maintain previous
>>>> behaviour.
>>>>
>>>> The following patchwork introduces CPPC: A newer method of
>>>> controlling CPU performance. The OS is not expected to support CPPC
>>>> and PSS at runtime. So the kconfig option lets us make these two
>>>> mutually exclusive at compile time.
>>>>
>>>> Signed-off-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
>>>> Reviewed-by: Al Stone <al.stone@linaro.org>
>>>> ---
>>>>  drivers/acpi/Kconfig            |  31 +++++++++--
>>>>  drivers/acpi/Makefile           |   7 ++-
>>>>  drivers/acpi/processor_driver.c |  86 ++++++++++++++++++----------
>>>>  drivers/cpufreq/Kconfig         |   2 +-
>>>>  drivers/cpufreq/Kconfig.x86     |   2 +
>>>>  include/acpi/processor.h        | 120 ++++++++++++++++++++++++++++------------
>>>>  6 files changed, 176 insertions(+), 72 deletions(-)
>>>>
>>>> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
>>>> index ab2cbb5..5942754 100644
>>>> --- a/drivers/acpi/Kconfig
>>>> +++ b/drivers/acpi/Kconfig
>>>> @@ -166,18 +166,39 @@ config ACPI_DOCK
>>>>         This driver supports ACPI-controlled docking stations and removable
>>>>         drive bays such as the IBM Ultrabay and the Dell Module Bay.
>>>>
>>>> -config ACPI_PROCESSOR
>>>> -     tristate "Processor"
>>>> -     select THERMAL
>>>> -     select CPU_IDLE
>>>> +config ACPI_CST
>>>> +     bool "ACPI C states (CST) driver"
>>>> +     depends on ACPI_PROCESSOR
>>>>       depends on X86 || IA64
>>>> +     select CPU_IDLE
>>>>       default y
>>>>       help
>>>>         This driver installs ACPI as the idle handler for Linux and uses
>>>>         ACPI C2 and C3 processor states to save power on systems that
>>>> -       support it.  It is required by several flavors of cpufreq
>>>> +       support it.
>>>> +
>>>> +config ACPI_PSS
>>>> +     bool "ACPI P States (PSS) driver"
>>>> +     depends on ACPI_PROCESSOR
>>>> +     depends on X86 || IA64
>>>> +     select THERMAL
>>>> +     default y
>>>> +     help
>>>> +       This driver implements ACPI methods for controlling CPU performance
>>>> +       using PSS methods as described in the ACPI spec. It also enables support
>>>> +       for ACPI based performance throttling (TSS) and ACPI based thermal
>>>> +       monitoring. It is required by several flavors of cpufreq
>>>>         performance-state drivers.
>>>
>>> For starters, I don't like these new Kconfig options.
>>>
>>> Isn't there a way to implement what you need without adding them?
>>
>> We need to use the ACPI Processor driver for CPPC without including
>> all its current dependencies. (i.e. PSS, TSS, CSS etc.). The upcoming
>> LPI work from Sudeep will also face the same issue. I considered the
>> alternative of adding a probe routine which matches
>> ACPI_PROCESSOR_OBJECT/DEVICE_HID to each driver, but this seemed like
>> a better option. Do you have any other ideas?
>
> First of all, I don't see what _CST has to do with CPPC.

Agree, it doesn't. I was implying that the current acpi processor
driver is tied to CST as well. CST and CPPC can co-exist. But Sudeep's
LPI patchwork would need to separate CST out of the processor driver
anyway. He actually proposed a similar-ish solution a while back.

>
> Second, it looks like the problem is that x86 probably won't use CPPC,
> while arm64 probably won't use _PSS.

Yep.

>
> That can be addressed by adding Kconfig options, but those options
> should not be user-selectable (because quite honestly users don't have
> to know what those things are and they don't care *and* things break
> if they make a wrong choice).  Instead, I'd make architecture Kconfigs
> select those options automatically.

Ok. I'll look into moving these config options into the ARCH_HAS_ ..
sort of variants.

Thanks,
Ashwin.
Ashwin Chaugule July 8, 2015, 1:56 p.m. | #3
Hi Sudeep,

On 8 July 2015 at 09:43, Sudeep Holla <sudeep.holla@arm.com> wrote:
>
>
> On 08/07/15 02:27, Ashwin Chaugule wrote:
>>
>> On 7 July 2015 at 21:07, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
>>>
>>> On Monday, June 15, 2015 04:09:06 PM Ashwin Chaugule wrote:
>>>>
>>>> The ACPI processor driver is currently tied too closely
>>>> to the ACPI C-states (CST), P-states (PSS) and other related
>>>> constructs for controlling CPU idle and CPU performance.
>>>>
>>>> The newer ACPI specification (v5.1 onwards) introduces
>>>> alternative methods to CST and PSS. These new mechanisms
>>>> are described within each ACPI Processor object and so they
>>>> need to be scanned whenever a new Processor object is detected.
>>>> This patch introduces two new Kconfig symbols to allow for
>>>> finer configurability among the various options for controlling
>>>> CPU idle and performance states. There is no change in functionality
>>>> and these options are defaulted to enabled to maintain previous
>>>> behaviour.
>>>>
>>>> The following patchwork introduces CPPC: A newer method of
>>>> controlling CPU performance. The OS is not expected to support CPPC
>>>> and PSS at runtime. So the kconfig option lets us make these two
>>>> mutually exclusive at compile time.
>>>>
>>>> Signed-off-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
>>>> Reviewed-by: Al Stone <al.stone@linaro.org>
>>>> ---
>>>>   drivers/acpi/Kconfig            |  31 +++++++++--
>>>>   drivers/acpi/Makefile           |   7 ++-
>>>>   drivers/acpi/processor_driver.c |  86 ++++++++++++++++++----------
>>>>   drivers/cpufreq/Kconfig         |   2 +-
>>>>   drivers/cpufreq/Kconfig.x86     |   2 +
>>>>   include/acpi/processor.h        | 120
>>>> ++++++++++++++++++++++++++++------------
>>>>   6 files changed, 176 insertions(+), 72 deletions(-)
>>>>
>>>> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
>>>> index ab2cbb5..5942754 100644
>>>> --- a/drivers/acpi/Kconfig
>>>> +++ b/drivers/acpi/Kconfig
>>>> @@ -166,18 +166,39 @@ config ACPI_DOCK
>>>>          This driver supports ACPI-controlled docking stations and
>>>> removable
>>>>          drive bays such as the IBM Ultrabay and the Dell Module Bay.
>>>>
>>>> -config ACPI_PROCESSOR
>>>> -     tristate "Processor"
>>>> -     select THERMAL
>>>> -     select CPU_IDLE
>>>> +config ACPI_CST
>>>> +     bool "ACPI C states (CST) driver"
>>>> +     depends on ACPI_PROCESSOR
>>>>        depends on X86 || IA64
>>>> +     select CPU_IDLE
>>>>        default y
>>>>        help
>>>>          This driver installs ACPI as the idle handler for Linux and
>>>> uses
>>>>          ACPI C2 and C3 processor states to save power on systems that
>>>> -       support it.  It is required by several flavors of cpufreq
>>>> +       support it.
>>>> +
>>>> +config ACPI_PSS
>>>> +     bool "ACPI P States (PSS) driver"
>>>> +     depends on ACPI_PROCESSOR
>>>> +     depends on X86 || IA64
>>>> +     select THERMAL
>>>> +     default y
>>>> +     help
>>>> +       This driver implements ACPI methods for controlling CPU
>>>> performance
>>>> +       using PSS methods as described in the ACPI spec. It also enables
>>>> support
>>>> +       for ACPI based performance throttling (TSS) and ACPI based
>>>> thermal
>>>> +       monitoring. It is required by several flavors of cpufreq
>>>>          performance-state drivers.
>>>
>>>
>>> For starters, I don't like these new Kconfig options.
>>>
>>> Isn't there a way to implement what you need without adding them?
>>
>>
>> We need to use the ACPI Processor driver for CPPC without including
>> all its current dependencies. (i.e. PSS, TSS, CSS etc.). The upcoming
>> LPI work from Sudeep will also face the same issue.
>
>
> Ashwin, I am trying to keep Kconfig options minimum, iff necessary and
> selected by ARCH code(i.e. not user selectable). Also I am not entirely
> sure if we need to make PSS and CPPC mutually exclusive.

Agree. Moving this to ARCH does seem like a better option. I need to
explore that some more. Per the ACPI spec, the OS is not expected to
support PSS and CPPC at runtime. I want to avoid getting into
whitelist/blacklist issues which would be inevitable if we keep both
available at runtime. Some of the X86 drivers run into this already.

>
> I had seen patches to support PSS on ARM and if we have to support
> single Image to handle both they can't be exclusive.

Theres been one attempt about 1.5 years ago and AFAIK those folks have
completely backed out of the ARM64 Server space . ;) We can revisit
when someone proposes a more recent solution for PSS on ARM64. It
shouldn't be too hard to change the Kconfig dependencies accordingly.

Regards,
Ashwin.
Ashwin Chaugule July 8, 2015, 7:16 p.m. | #4
Hi Rafael,

On 8 July 2015 at 09:34, Rafael J. Wysocki <rafael@kernel.org> wrote:
> Hi Ashwin,
>
> On Wed, Jul 8, 2015 at 3:27 AM, Ashwin Chaugule
> <ashwin.chaugule@linaro.org> wrote:
>> On 7 July 2015 at 21:07, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
>>> On Monday, June 15, 2015 04:09:06 PM Ashwin Chaugule wrote:
>>>> The ACPI processor driver is currently tied too closely
>>>> to the ACPI C-states (CST), P-states (PSS) and other related
>>>> constructs for controlling CPU idle and CPU performance.
>>>>
>>>> The newer ACPI specification (v5.1 onwards) introduces
>>>> alternative methods to CST and PSS. These new mechanisms
>>>> are described within each ACPI Processor object and so they
>>>> need to be scanned whenever a new Processor object is detected.
>>>> This patch introduces two new Kconfig symbols to allow for
>>>> finer configurability among the various options for controlling
>>>> CPU idle and performance states. There is no change in functionality
>>>> and these options are defaulted to enabled to maintain previous
>>>> behaviour.
>>>>
>>>> The following patchwork introduces CPPC: A newer method of
>>>> controlling CPU performance. The OS is not expected to support CPPC
>>>> and PSS at runtime. So the kconfig option lets us make these two
>>>> mutually exclusive at compile time.
>>>>
>>>> Signed-off-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
>>>> Reviewed-by: Al Stone <al.stone@linaro.org>
>>>> ---
>>>>  drivers/acpi/Kconfig            |  31 +++++++++--
>>>>  drivers/acpi/Makefile           |   7 ++-
>>>>  drivers/acpi/processor_driver.c |  86 ++++++++++++++++++----------
>>>>  drivers/cpufreq/Kconfig         |   2 +-
>>>>  drivers/cpufreq/Kconfig.x86     |   2 +
>>>>  include/acpi/processor.h        | 120 ++++++++++++++++++++++++++++------------
>>>>  6 files changed, 176 insertions(+), 72 deletions(-)
>>>>
>>>> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
>>>> index ab2cbb5..5942754 100644
>>>> --- a/drivers/acpi/Kconfig
>>>> +++ b/drivers/acpi/Kconfig
>>>> @@ -166,18 +166,39 @@ config ACPI_DOCK
>>>>         This driver supports ACPI-controlled docking stations and removable
>>>>         drive bays such as the IBM Ultrabay and the Dell Module Bay.
>>>>
>>>> -config ACPI_PROCESSOR
>>>> -     tristate "Processor"
>>>> -     select THERMAL
>>>> -     select CPU_IDLE
>>>> +config ACPI_CST
>>>> +     bool "ACPI C states (CST) driver"
>>>> +     depends on ACPI_PROCESSOR
>>>>       depends on X86 || IA64
>>>> +     select CPU_IDLE
>>>>       default y
>>>>       help
>>>>         This driver installs ACPI as the idle handler for Linux and uses
>>>>         ACPI C2 and C3 processor states to save power on systems that
>>>> -       support it.  It is required by several flavors of cpufreq
>>>> +       support it.
>>>> +
>>>> +config ACPI_PSS
>>>> +     bool "ACPI P States (PSS) driver"
>>>> +     depends on ACPI_PROCESSOR
>>>> +     depends on X86 || IA64
>>>> +     select THERMAL
>>>> +     default y
>>>> +     help
>>>> +       This driver implements ACPI methods for controlling CPU performance
>>>> +       using PSS methods as described in the ACPI spec. It also enables support
>>>> +       for ACPI based performance throttling (TSS) and ACPI based thermal
>>>> +       monitoring. It is required by several flavors of cpufreq
>>>>         performance-state drivers.
>>>
>>> For starters, I don't like these new Kconfig options.
>>>
>>> Isn't there a way to implement what you need without adding them?
>>
>> We need to use the ACPI Processor driver for CPPC without including
>> all its current dependencies. (i.e. PSS, TSS, CSS etc.). The upcoming
>> LPI work from Sudeep will also face the same issue. I considered the
>> alternative of adding a probe routine which matches
>> ACPI_PROCESSOR_OBJECT/DEVICE_HID to each driver, but this seemed like
>> a better option. Do you have any other ideas?
>
> First of all, I don't see what _CST has to do with CPPC.
>
> Second, it looks like the problem is that x86 probably won't use CPPC,
> while arm64 probably won't use _PSS.
>
> That can be addressed by adding Kconfig options, but those options
> should not be user-selectable (because quite honestly users don't have
> to know what those things are and they don't care *and* things break
> if they make a wrong choice).  Instead, I'd make architecture Kconfigs
> select those options automatically.
>

I've made changes locally. Basically s/ACPI_PSS/HAVE_ACPI_PSS/ and in
arch/x86/Kconfig; select HAVE_ACPI_PSS if ACPI. Similarly for CST.
Just wanted to check if there were any other comments before sending
out v7.

Thanks,
Ashwin.

Patch

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index ab2cbb5..5942754 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -166,18 +166,39 @@  config ACPI_DOCK
 	  This driver supports ACPI-controlled docking stations and removable
 	  drive bays such as the IBM Ultrabay and the Dell Module Bay.
 
-config ACPI_PROCESSOR
-	tristate "Processor"
-	select THERMAL
-	select CPU_IDLE
+config ACPI_CST
+	bool "ACPI C states (CST) driver"
+	depends on ACPI_PROCESSOR
 	depends on X86 || IA64
+	select CPU_IDLE
 	default y
 	help
 	  This driver installs ACPI as the idle handler for Linux and uses
 	  ACPI C2 and C3 processor states to save power on systems that
-	  support it.  It is required by several flavors of cpufreq
+	  support it.
+
+config ACPI_PSS
+	bool "ACPI P States (PSS) driver"
+	depends on ACPI_PROCESSOR
+	depends on X86 || IA64
+	select THERMAL
+	default y
+	help
+	  This driver implements ACPI methods for controlling CPU performance
+	  using PSS methods as described in the ACPI spec. It also enables support
+	  for ACPI based performance throttling (TSS) and ACPI based thermal
+	  monitoring. It is required by several flavors of cpufreq
 	  performance-state drivers.
 
+config ACPI_PROCESSOR
+	tristate "Processor"
+	depends on X86 || IA64
+	default y
+	help
+	  This driver adds support for the ACPI Processor package. It is required
+	  by several flavors of cpufreq performance-state, thermal, throttling and
+	  idle drivers.
+
 	  To compile this driver as a module, choose M here:
 	  the module will be called processor.
 
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 8a063e2..30b2bfc 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -82,9 +82,10 @@  obj-$(CONFIG_ACPI_CUSTOM_METHOD)+= custom_method.o
 obj-$(CONFIG_ACPI_BGRT)		+= bgrt.o
 
 # processor has its own "processor." module_param namespace
-processor-y			:= processor_driver.o processor_throttling.o
-processor-y			+= processor_idle.o processor_thermal.o
-processor-$(CONFIG_CPU_FREQ)	+= processor_perflib.o
+processor-y			:= processor_driver.o
+processor-$(CONFIG_ACPI_CST)	+= processor_idle.o
+processor-$(CONFIG_ACPI_PSS)	+= processor_perflib.o	\
+	processor_throttling.o processor_thermal.o
 
 obj-$(CONFIG_ACPI_PROCESSOR_AGGREGATOR) += acpi_pad.o
 
diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c
index d9f7158..64aa638 100644
--- a/drivers/acpi/processor_driver.c
+++ b/drivers/acpi/processor_driver.c
@@ -163,34 +163,24 @@  static struct notifier_block __refdata acpi_cpu_notifier = {
 	    .notifier_call = acpi_cpu_soft_notify,
 };
 
-static int __acpi_processor_start(struct acpi_device *device)
+#ifdef CONFIG_ACPI_PSS
+static int acpi_pss_perf_init(struct acpi_processor *pr,
+		struct acpi_device *device)
 {
-	struct acpi_processor *pr = acpi_driver_data(device);
-	acpi_status status;
 	int result = 0;
 
-	if (!pr)
-		return -ENODEV;
-
-	if (pr->flags.need_hotplug_init)
-		return 0;
-
-#ifdef CONFIG_CPU_FREQ
 	acpi_processor_ppc_has_changed(pr, 0);
-#endif
+
 	acpi_processor_get_throttling_info(pr);
 
 	if (pr->flags.throttling)
 		pr->flags.limit = 1;
 
-	if (!cpuidle_get_driver() || cpuidle_get_driver() == &acpi_idle_driver)
-		acpi_processor_power_init(pr);
-
 	pr->cdev = thermal_cooling_device_register("Processor", device,
 						   &processor_cooling_ops);
 	if (IS_ERR(pr->cdev)) {
 		result = PTR_ERR(pr->cdev);
-		goto err_power_exit;
+		return result;
 	}
 
 	dev_dbg(&device->dev, "registered as cooling_device%d\n",
@@ -204,6 +194,7 @@  static int __acpi_processor_start(struct acpi_device *device)
 			"Failed to create sysfs link 'thermal_cooling'\n");
 		goto err_thermal_unregister;
 	}
+
 	result = sysfs_create_link(&pr->cdev->device.kobj,
 				   &device->dev.kobj,
 				   "device");
@@ -213,17 +204,61 @@  static int __acpi_processor_start(struct acpi_device *device)
 		goto err_remove_sysfs_thermal;
 	}
 
-	status = acpi_install_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
-					     acpi_processor_notify, device);
-	if (ACPI_SUCCESS(status))
-		return 0;
-
 	sysfs_remove_link(&pr->cdev->device.kobj, "device");
  err_remove_sysfs_thermal:
 	sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
  err_thermal_unregister:
 	thermal_cooling_device_unregister(pr->cdev);
- err_power_exit:
+
+	return result;
+}
+
+static void acpi_pss_perf_exit(struct acpi_processor *pr,
+		struct acpi_device *device)
+{
+	if (pr->cdev) {
+		sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
+		sysfs_remove_link(&pr->cdev->device.kobj, "device");
+		thermal_cooling_device_unregister(pr->cdev);
+		pr->cdev = NULL;
+	}
+}
+#else
+static inline int acpi_pss_perf_init(struct acpi_processor *pr,
+		struct acpi_device *device)
+{
+	return 0;
+}
+
+static inline void acpi_pss_perf_exit(struct acpi_processor *pr,
+		struct acpi_device *device) {}
+#endif /* CONFIG_ACPI_PSS */
+
+static int __acpi_processor_start(struct acpi_device *device)
+{
+	struct acpi_processor *pr = acpi_driver_data(device);
+	acpi_status status;
+	int result = 0;
+
+	if (!pr)
+		return -ENODEV;
+
+	if (pr->flags.need_hotplug_init)
+		return 0;
+
+	if (!cpuidle_get_driver() || cpuidle_get_driver() == &acpi_idle_driver)
+		acpi_processor_power_init(pr);
+
+	result = acpi_pss_perf_init(pr, device);
+	if (result)
+		goto err_power_exit;
+
+	status = acpi_install_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
+					     acpi_processor_notify, device);
+	if (ACPI_SUCCESS(status))
+		return 0;
+
+err_power_exit:
 	acpi_processor_power_exit(pr);
 	return result;
 }
@@ -252,15 +287,10 @@  static int acpi_processor_stop(struct device *dev)
 	pr = acpi_driver_data(device);
 	if (!pr)
 		return 0;
-
 	acpi_processor_power_exit(pr);
 
-	if (pr->cdev) {
-		sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
-		sysfs_remove_link(&pr->cdev->device.kobj, "device");
-		thermal_cooling_device_unregister(pr->cdev);
-		pr->cdev = NULL;
-	}
+	acpi_pss_perf_exit(pr, device);
+
 	return 0;
 }
 
diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
index 659879a..2f36e2a 100644
--- a/drivers/cpufreq/Kconfig
+++ b/drivers/cpufreq/Kconfig
@@ -223,7 +223,7 @@  endif
 if IA64
 config IA64_ACPI_CPUFREQ
 	tristate "ACPI Processor P-States driver"
-	depends on ACPI_PROCESSOR
+	depends on ACPI_PROCESSOR && ACPI_PSS && ACPI_CST
 	help
 	This driver adds a CPUFreq driver which utilizes the ACPI
 	Processor Performance States.
diff --git a/drivers/cpufreq/Kconfig.x86 b/drivers/cpufreq/Kconfig.x86
index c59bdcb..ee285a8 100644
--- a/drivers/cpufreq/Kconfig.x86
+++ b/drivers/cpufreq/Kconfig.x86
@@ -18,6 +18,7 @@  config X86_INTEL_PSTATE
 config X86_PCC_CPUFREQ
 	tristate "Processor Clocking Control interface driver"
 	depends on ACPI && ACPI_PROCESSOR
+	depends on ACPI_PSS && ACPI_CST
 	help
 	  This driver adds support for the PCC interface.
 
@@ -32,6 +33,7 @@  config X86_PCC_CPUFREQ
 config X86_ACPI_CPUFREQ
 	tristate "ACPI Processor P-States driver"
 	depends on ACPI_PROCESSOR
+	depends on ACPI_PSS && ACPI_CST
 	help
 	  This driver adds a CPUFreq driver which utilizes the ACPI
 	  Processor Performance States.
diff --git a/include/acpi/processor.h b/include/acpi/processor.h
index 4188a4d..b76d05b 100644
--- a/include/acpi/processor.h
+++ b/include/acpi/processor.h
@@ -222,16 +222,6 @@  struct acpi_processor_errata {
 	} piix4;
 };
 
-extern int acpi_processor_preregister_performance(struct
-						  acpi_processor_performance
-						  __percpu *performance);
-
-extern int acpi_processor_register_performance(struct acpi_processor_performance
-					       *performance, unsigned int cpu);
-extern void acpi_processor_unregister_performance(struct
-						  acpi_processor_performance
-						  *performance,
-						  unsigned int cpu);
 
 /* note: this locks both the calling module and the processor module
          if a _PPC object exists, rmmod is disallowed then */
@@ -267,28 +257,52 @@  static inline int acpi_processor_ffh_cstate_probe(unsigned int cpu,
 	return -1;
 }
 static inline void acpi_processor_ffh_cstate_enter(struct acpi_processor_cx
-						   *cstate)
-{
-	return;
-}
+						   *cstate) {}
 #endif
 
 /* in processor_perflib.c */
 
-#ifdef CONFIG_CPU_FREQ
+#ifdef CONFIG_ACPI_PSS
+extern int acpi_processor_preregister_performance(struct
+						  acpi_processor_performance
+						  __percpu *performance);
+
+extern int acpi_processor_register_performance(struct acpi_processor_performance
+					       *performance, unsigned int cpu);
+extern void acpi_processor_unregister_performance(struct
+						  acpi_processor_performance
+						  *performance,
+						  unsigned int cpu);
 void acpi_processor_ppc_init(void);
 void acpi_processor_ppc_exit(void);
 int acpi_processor_ppc_has_changed(struct acpi_processor *pr, int event_flag);
 extern int acpi_processor_get_bios_limit(int cpu, unsigned int *limit);
 #else
-static inline void acpi_processor_ppc_init(void)
+static inline int acpi_processor_preregister_performance(struct
+		acpi_processor_performance
+		__percpu *performance)
 {
-	return;
+	return -ENODEV;
+
 }
-static inline void acpi_processor_ppc_exit(void)
+
+static inline int acpi_processor_register_performance(struct
+		acpi_processor_performance
+		*performance, unsigned int cpu)
 {
-	return;
+	return -ENODEV;
+
 }
+
+static inline void acpi_processor_unregister_performance(struct
+		acpi_processor_performance
+		*performance,
+		unsigned int cpu) {}
+
+static inline void acpi_processor_ppc_init(void) {}
+
+static inline void acpi_processor_ppc_exit(void) {}
+
 static inline int acpi_processor_ppc_has_changed(struct acpi_processor *pr,
 								int event_flag)
 {
@@ -302,12 +316,12 @@  static inline int acpi_processor_ppc_has_changed(struct acpi_processor *pr,
 	}
 	return 0;
 }
+
 static inline int acpi_processor_get_bios_limit(int cpu, unsigned int *limit)
 {
 	return -ENODEV;
 }
-
-#endif				/* CONFIG_CPU_FREQ */
+#endif				/* CONFIG_ACPI_PSS */
 
 /* in processor_core.c */
 phys_cpuid_t acpi_get_phys_id(acpi_handle, int type, u32 acpi_id);
@@ -318,6 +332,7 @@  int acpi_get_cpuid(acpi_handle, int type, u32 acpi_id);
 void acpi_processor_set_pdc(acpi_handle handle);
 
 /* in processor_throttling.c */
+#ifdef CONFIG_ACPI_PSS
 int acpi_processor_tstate_has_changed(struct acpi_processor *pr);
 int acpi_processor_get_throttling_info(struct acpi_processor *pr);
 extern int acpi_processor_set_throttling(struct acpi_processor *pr,
@@ -330,36 +345,71 @@  extern void acpi_processor_reevaluate_tstate(struct acpi_processor *pr,
 			unsigned long action);
 extern const struct file_operations acpi_processor_throttling_fops;
 extern void acpi_processor_throttling_init(void);
+#else
+static inline int acpi_processor_tstate_has_changed(struct acpi_processor *pr)
+{
+	return 0;
+}
+
+static inline int acpi_processor_get_throttling_info(struct acpi_processor *pr)
+{
+	return -ENODEV;
+}
+
+static inline int acpi_processor_set_throttling(struct acpi_processor *pr,
+					 int state, bool force)
+{
+	return -ENODEV;
+}
+
+static inline void acpi_processor_reevaluate_tstate(struct acpi_processor *pr,
+			unsigned long action) {}
+
+static inline void acpi_processor_throttling_init(void) {}
+#endif	/* CONFIG_ACPI_PSS */
+
 /* in processor_idle.c */
+extern struct cpuidle_driver acpi_idle_driver;
+#ifdef CONFIG_ACPI_CST
 int acpi_processor_power_init(struct acpi_processor *pr);
 int acpi_processor_power_exit(struct acpi_processor *pr);
 int acpi_processor_cst_has_changed(struct acpi_processor *pr);
 int acpi_processor_hotplug(struct acpi_processor *pr);
-extern struct cpuidle_driver acpi_idle_driver;
-
-#ifdef CONFIG_PM_SLEEP
 void acpi_processor_syscore_init(void);
 void acpi_processor_syscore_exit(void);
 #else
+static inline int acpi_processor_power_init(struct acpi_processor *pr)
+{
+	return -ENODEV;
+}
+
+static inline int acpi_processor_power_exit(struct acpi_processor *pr)
+{
+	return -ENODEV;
+}
+
+static inline int acpi_processor_cst_has_changed(struct acpi_processor *pr)
+{
+	return -ENODEV;
+}
+
+static inline int acpi_processor_hotplug(struct acpi_processor *pr)
+{
+	return -ENODEV;
+}
 static inline void acpi_processor_syscore_init(void) {}
 static inline void acpi_processor_syscore_exit(void) {}
-#endif
+#endif	/* CONFIG_ACPI_CST */
 
 /* in processor_thermal.c */
 int acpi_processor_get_limit_info(struct acpi_processor *pr);
+#ifdef CONFIG_ACPI_PSS
 extern const struct thermal_cooling_device_ops processor_cooling_ops;
-#ifdef CONFIG_CPU_FREQ
 void acpi_thermal_cpufreq_init(void);
 void acpi_thermal_cpufreq_exit(void);
 #else
-static inline void acpi_thermal_cpufreq_init(void)
-{
-	return;
-}
-static inline void acpi_thermal_cpufreq_exit(void)
-{
-	return;
-}
-#endif
+static inline void acpi_thermal_cpufreq_init(void) {}
+static inline void acpi_thermal_cpufreq_exit(void) {}
+#endif	/* CONFIG_ACPI_PSS */
 
 #endif