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Commit c1c30634 authored by Alexey Starikovskiy's avatar Alexey Starikovskiy Committed by Ingo Molnar
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ACPI: Set max_cstate to 1 for early Opterons. 

AMD Opteron processors before CG revision don't like C-states > 1.

This solves the long standing bugzilla #5303 and probably some more
on affected machines:

  http://bugzilla.kernel.org/show_bug.cgi?id=5303



[ tglx@linutronix.de: reworked the patch so it does not wreck ia64 ]

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent d4d25dec

drivers/acpi/processor_idle.c

+1 −0
Original line number Diff line number Diff line
@@ -1658,6 +1658,7 @@ int __cpuinit acpi_processor_power_init(struct acpi_processor *pr, 


	if (!first_run) {

		dmi_check_system(processor_power_dmi_table);

		max_cstate = acpi_processor_cstate_check(max_cstate);

		if (max_cstate < ACPI_C_STATES_MAX)

			printk(KERN_NOTICE

			       "ACPI: processor limited to max C-state %d\n",

include/asm-ia64/acpi.h

+1 −0
Original line number Diff line number Diff line
@@ -94,6 +94,7 @@ ia64_acpi_release_global_lock (unsigned int *lock) 
#define acpi_noirq 0	/* ACPI always enabled on IA64 */

#define acpi_pci_disabled 0 /* ACPI PCI always enabled on IA64 */

#define acpi_strict 1	/* no ACPI spec workarounds on IA64 */

#define acpi_processor_cstate_check(x) (x) /* no idle limits on IA64 :) */

static inline void disable_acpi(void) { }



const char *acpi_get_sysname (void);

include/asm-x86/acpi.h

+27 −0
Original line number Diff line number Diff line 
#ifndef _ASM_X86_ACPI_H

#define _ASM_X86_ACPI_H



#ifdef CONFIG_X86_32

# include "acpi_32.h"

#else

# include "acpi_64.h"

#endif



#include <asm/processor.h>



/*

 * Check if the CPU can handle C2 and deeper

 */

static inline unsigned int acpi_processor_cstate_check(unsigned int max_cstate)

{

	/*

	 * Early models (<=5) of AMD Opterons are not supposed to go into

	 * C2 state.

	 *

	 * Steppings 0x0A and later are good

	 */

	if (boot_cpu_data.x86 == 0x0F &&

	    boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&

	    boot_cpu_data.x86_model <= 0x05 &&

	    boot_cpu_data.x86_mask < 0x0A)

		return 1;

	else

		return max_cstate;

}



#endif