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ACPI: Load acpi-cpufreq from processor driver automatically

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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: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Renninger <trenn@suse.de>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Andi Kleen
2012-01-26 00:09:08 +01:00
committed by Greg Kroah-Hartman
parent b66b8b9a4a
commit 9061e0e167
3 changed files with 24 additions and 0 deletions
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22
drivers/acpi/processor_perflib.c
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@@ -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;