Commit 9061e0e1 authored by Andi Kleen's avatar Andi Kleen Committed by Greg Kroah-Hartman
Browse files

ACPI: Load acpi-cpufreq from processor driver automatically 



The only left over hole in automatic cpufreq driver loading was the loading
of ACPI cpufreq. This driver should be loaded when ACPI supports a _PDC
method and the CPU vendor wants to use acpi cpufreq.

Simply add a request module call to the acpi processor core driver
when this is true. This seems like the simplest solution for this.

Cc: Len Brown <lenb@kernel.org>
Signed-off-by: default avatarAndi Kleen <ak@linux.intel.com>
Signed-off-by: default avatarThomas Renninger <trenn@suse.de>
Acked-by: default avatarH. Peter Anvin <hpa@zytor.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent b66b8b9a

drivers/acpi/processor_driver.c

+1 −0
Original line number Diff line number Diff line
@@ -497,6 +497,7 @@ static int __cpuinit acpi_processor_add(struct acpi_device *device) 


#ifdef CONFIG_CPU_FREQ

	acpi_processor_ppc_has_changed(pr, 0);

	acpi_processor_load_module(pr);

#endif

	acpi_processor_get_throttling_info(pr);

	acpi_processor_get_limit_info(pr);

drivers/acpi/processor_perflib.c

+22 −0
Original line number Diff line number Diff line
@@ -240,6 +240,28 @@ void acpi_processor_ppc_exit(void) 
	acpi_processor_ppc_status &= ~PPC_REGISTERED;

}



/*

 * Do a quick check if the systems looks like it should use ACPI

 * cpufreq. We look at a _PCT method being available, but don't

 * do a whole lot of sanity checks.

 */

void acpi_processor_load_module(struct acpi_processor *pr)

{

	static int requested;

	acpi_status status = 0;

	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };



	if (!arch_has_acpi_pdc() || requested)

		return;

	status = acpi_evaluate_object(pr->handle, "_PCT", NULL, &buffer);

	if (!ACPI_FAILURE(status)) {

		printk(KERN_INFO PREFIX "Requesting acpi_cpufreq\n");

		request_module_nowait("acpi_cpufreq");

		requested = 1;

	}

	kfree(buffer.pointer);

}



static int acpi_processor_get_performance_control(struct acpi_processor *pr)

{

	int result = 0;

include/acpi/processor.h

+1 −0
Original line number Diff line number Diff line
@@ -224,6 +224,7 @@ struct acpi_processor_errata { 
	} piix4;

};



extern void acpi_processor_load_module(struct acpi_processor *pr);

extern int acpi_processor_preregister_performance(struct

						  acpi_processor_performance

						  __percpu *performance);

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