cpuidle: ACPI processor idle regression

Sorry, a bad copy/paste address for Rafael.

----

Hi all,

while testing the processor_idle for ACPI, I noticed the states usage is not used for cpuidle in sysfs.

Reproduced on Lenovo x230, with a i7-3520M CPU @ 2.90GHz without the intel_idle driver.

After git-bisecting, the commit where this regression occurs is:

ac212b6980d8d5eda705864fc5a8ecddc6d6eacc is the first bad commit commit ac212b6980d8d5eda705864fc5a8ecddc6d6eacc

Author: Rafael J. Wysocki <[email protected]>
Date:   Fri May 3 00:26:22 2013 +0200

ACPI / processor: Use common hotplug infrastructure

Split the ACPI processor driver into two parts, one that is non-modular, resides in the ACPI core and handles the enumeration and hotplug of processors and one that implements the rest of the existing processor driver functionality.

The non-modular part uses an ACPI scan handler object to enumerate processors on the basis of information provided by the ACPI namespace and to hook up with the common ACPI hotplug infrastructure. It also populates the ACPI handle of each processor device having a corresponding object in the ACPI namespace, which allows the driver proper to bind to those devices, and makes the driver bind to them if it is readily available (i.e. loaded) when the scan handler's .attach() routine is running.

There are a few reasons to make this change.

First, switching the ACPI processor driver to using the common ACPI hotplug infrastructure reduces code duplication and size considerably, even though a new file is created along with a header comment etc.

Second, since the common hotplug code attempts to offline devices before starting the (non-reversible) removal procedure, it will abort (and possibly roll back) hot-remove operations involving processors if cpu_down() returns an error code for one of them instead of continuing them blindly (if /sys/firmware/acpi/hotplug/force_remove is unset). That is a more desirable behavior than what the current code does.

Finally, the separation of the scan/hotplug part from the driver proper makes it possible to simplify the driver's .remove() routine, because it doesn't need to worry about the possible cleanup related to processor removal any more (the scan/hotplug part is responsible for that now) and can handle device removal and driver removal symmetricaly (i.e. as appropriate).

Some user-visible changes in sysfs are made (for example, the 'sysdev' link from the ACPI device node to the processor device's directory is gone and a 'physical_node' link is present instead and a corresponding 'firmware_node' is present in the processor device's directory, the processor driver is now visible under /sys/bus/cpu/drivers/ and bound to the processor device), but that shouldn't affect the functionality that users care about (frequency scaling, C-states and thermal management).

Tested on my venerable Toshiba Portege R500.

Signed-off-by Rafael J. Wysocki <[email protected]>

Acked-by Greg Kroah-Hartman <[email protected]>

Reviewed-by Toshi Kani <[email protected]>

Quoted 10 lines · Daniel Lezcano

Sorry, a bad copy/paste address for Rafael.

----

Hi all,

while testing the processor_idle for ACPI, I noticed the states usage is not used for cpuidle in sysfs.

Quoted 4 lines

Reproduced on Lenovo x230, with a i7-3520M CPU @ 2.90GHz without the intel_idle driver.

After git-bisecting, the commit where this regression occurs is:

Reproduced and investigating that.

Quoted 11 lines · Rafael J. Wysocki

Quoted 10 lines · Daniel Lezcano

Sorry, a bad copy/paste address for Rafael.

----

Hi all,

while testing the processor_idle for ACPI, I noticed the states usage is not used for cpuidle in sysfs.

Quoted 6 lines

Quoted 4 lines

Reproduced on Lenovo x230, with a i7-3520M CPU @ 2.90GHz without the intel_idle driver.

After git-bisecting, the commit where this regression occurs is:

Reproduced and investigating that.

The appended patch fixes this for me. Can you please verify?

---
 drivers/acpi/acpi_processor.c   |    5 +++++
 drivers/acpi/processor_driver.c |    3 ---
 2 files changed, 5 insertions(+), 3 deletions(-)

Index: linux-pm/drivers/acpi/processor_driver.c
===================================================================

drivers/acpi/processor_driver.c +0 -3

@@ -78,9 +78,6 @@ static struct device_driver acpi_process
 	.remove = acpi_processor_stop,
 };
 
-DEFINE_PER_CPU(struct acpi_processor *, processors);
-EXPORT_PER_CPU_SYMBOL(processors);
-
 static void acpi_processor_notify(acpi_handle handle, u32 event, void *data)
 {
 	struct acpi_device *device = data;

Index: linux-pm/drivers/acpi/acpi_processor.c
===================================================================

drivers/acpi/acpi_processor.c +5 -1

@@ -29,6 +29,9 @@
 
 ACPI_MODULE_NAME("processor");
 
+DEFINE_PER_CPU(struct acpi_processor *, processors);
+EXPORT_PER_CPU_SYMBOL(processors);
+
 /* --------------------------------------------------------------------------
                                 Errata Handling
    -------------------------------------------------------------------------- */

@@ -387,6 +390,7 @@ static int __cpuinit acpi_processor_add(
 	 * checks.
 	 */
 	per_cpu(processor_device_array, pr->id) = device;
+	per_cpu(processors, pr->id) = pr;
 
 	dev = get_cpu_device(pr->id);
 	result = acpi_bind_one(dev, pr->handle);

@@ -406,6 +410,7 @@ static int __cpuinit acpi_processor_add(
  err:
 	free_cpumask_var(pr->throttling.shared_cpu_map);
 	device->driver_data = NULL;
+	per_cpu(processors, pr->id) = NULL;
  err_free_pr:
 	kfree(pr);
 	return result;
 
--

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