kernel-ark/arch/x86/kernel/acpi/processor.c
Zhao Yakui 5b53496a5a ACPI: Disable the C2C3_FFH access mode HW has no MWAIT support
991528d734
(ACPI: Processor native C-states using MWAIT)
started passing C2C3_FFH to _PDC to tell the BIOS
that Linux supports MWAIT for deep C-states.

However, we should first double check with the hardware
that it actually supports MWAIT before potentially exposing
a BIOS bug of an MWAIT _CST on HW that doesn't support MWAIT.

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Li Shaohua <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
2008-07-16 23:27:04 +02:00

88 lines
2.0 KiB
C

/*
* Copyright (C) 2005 Intel Corporation
* Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
* - Added _PDC for platforms with Intel CPUs
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/acpi.h>
#include <acpi/processor.h>
#include <asm/acpi.h>
static void init_intel_pdc(struct acpi_processor *pr, struct cpuinfo_x86 *c)
{
struct acpi_object_list *obj_list;
union acpi_object *obj;
u32 *buf;
/* allocate and initialize pdc. It will be used later. */
obj_list = kmalloc(sizeof(struct acpi_object_list), GFP_KERNEL);
if (!obj_list) {
printk(KERN_ERR "Memory allocation error\n");
return;
}
obj = kmalloc(sizeof(union acpi_object), GFP_KERNEL);
if (!obj) {
printk(KERN_ERR "Memory allocation error\n");
kfree(obj_list);
return;
}
buf = kmalloc(12, GFP_KERNEL);
if (!buf) {
printk(KERN_ERR "Memory allocation error\n");
kfree(obj);
kfree(obj_list);
return;
}
buf[0] = ACPI_PDC_REVISION_ID;
buf[1] = 1;
buf[2] = ACPI_PDC_C_CAPABILITY_SMP;
/*
* The default of PDC_SMP_T_SWCOORD bit is set for intel x86 cpu so
* that OSPM is capable of native ACPI throttling software
* coordination using BIOS supplied _TSD info.
*/
buf[2] |= ACPI_PDC_SMP_T_SWCOORD;
if (cpu_has(c, X86_FEATURE_EST))
buf[2] |= ACPI_PDC_EST_CAPABILITY_SWSMP;
if (cpu_has(c, X86_FEATURE_ACPI))
buf[2] |= ACPI_PDC_T_FFH;
/*
* If mwait/monitor is unsupported, C2/C3_FFH will be disabled
*/
if (!cpu_has(c, X86_FEATURE_MWAIT))
buf[2] &= ~(ACPI_PDC_C_C2C3_FFH);
obj->type = ACPI_TYPE_BUFFER;
obj->buffer.length = 12;
obj->buffer.pointer = (u8 *) buf;
obj_list->count = 1;
obj_list->pointer = obj;
pr->pdc = obj_list;
return;
}
/* Initialize _PDC data based on the CPU vendor */
void arch_acpi_processor_init_pdc(struct acpi_processor *pr)
{
struct cpuinfo_x86 *c = &cpu_data(pr->id);
pr->pdc = NULL;
if (c->x86_vendor == X86_VENDOR_INTEL)
init_intel_pdc(pr, c);
return;
}
EXPORT_SYMBOL(arch_acpi_processor_init_pdc);