Commit d1896049 authored by Thomas Renninger's avatar Thomas Renninger Committed by Len Brown
Browse files

ACPI, intel_idle: Cleanup idle= internal variables 



Having four variables for the same thing:
  idle_halt, idle_nomwait, force_mwait and boot_option_idle_overrides
is rather confusing and unnecessary complex.

if idle= boot param is passed, only set up one variable:
boot_option_idle_overrides

Introduces following functional changes/fixes:
  - intel_idle driver does not register if any idle=xy
    boot param is passed.
  - processor_idle.c will also not register a cpuidle driver
    and get active if idle=halt is passed.
    Before a cpuidle driver with one (C1, halt) state got registered
    Now the default_idle function will be used which finally uses
    the same idle call to enter sleep state (safe_halt()), but
    without registering a whole cpuidle driver.

That means idle= param will always avoid cpuidle drivers to register
with one exception (same behavior as before):
idle=nomwait
may still register acpi_idle cpuidle driver, but C1 will not use
mwait, but hlt. This can be a workaround for IO based deeper sleep
states where C1 mwait causes problems.

Signed-off-by: default avatarThomas Renninger <trenn@suse.de>
cc: x86@kernel.org
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent d8c216cf

arch/ia64/include/asm/processor.h

+3 −2
Original line number Diff line number Diff line
@@ -717,8 +717,9 @@ prefetchw (const void *x) 
#define spin_lock_prefetch(x)	prefetchw(x)



extern unsigned long boot_option_idle_override;

extern unsigned long idle_halt;

extern unsigned long idle_nomwait;



enum idle_boot_override {IDLE_NO_OVERRIDE=0, IDLE_HALT, IDLE_FORCE_MWAIT,

			 IDLE_NOMWAIT, IDLE_POLL};



#endif /* !__ASSEMBLY__ */

arch/ia64/kernel/process.c

+1 −5
Original line number Diff line number Diff line
@@ -53,12 +53,8 @@ 


void (*ia64_mark_idle)(int);



unsigned long boot_option_idle_override = 0;

unsigned long boot_option_idle_override = IDLE_NO_OVERRIDE;

EXPORT_SYMBOL(boot_option_idle_override);

unsigned long idle_halt;

EXPORT_SYMBOL(idle_halt);

unsigned long idle_nomwait;

EXPORT_SYMBOL(idle_nomwait);

void (*pm_idle) (void);

EXPORT_SYMBOL(pm_idle);

void (*pm_power_off) (void);

arch/x86/include/asm/processor.h

+3 −2
Original line number Diff line number Diff line
@@ -762,10 +762,11 @@ extern void select_idle_routine(const struct cpuinfo_x86 *c); 
extern void init_c1e_mask(void);



extern unsigned long		boot_option_idle_override;

extern unsigned long		idle_halt;

extern unsigned long		idle_nomwait;

extern bool			c1e_detected;



enum idle_boot_override {IDLE_NO_OVERRIDE=0, IDLE_HALT, IDLE_NOMWAIT,

			 IDLE_POLL, IDLE_FORCE_MWAIT};



extern void enable_sep_cpu(void);

extern int sysenter_setup(void);

arch/x86/kernel/process.c

+8 −16
Original line number Diff line number Diff line
@@ -22,11 +22,6 @@ 
#include <asm/i387.h>

#include <asm/debugreg.h>



unsigned long idle_halt;

EXPORT_SYMBOL(idle_halt);

unsigned long idle_nomwait;

EXPORT_SYMBOL(idle_nomwait);



struct kmem_cache *task_xstate_cachep;

EXPORT_SYMBOL_GPL(task_xstate_cachep);
@@ -328,7 +323,7 @@ long sys_execve(const char __user *name, 
/*

 * Idle related variables and functions

 */

unsigned long boot_option_idle_override = 0;

unsigned long boot_option_idle_override = IDLE_NO_OVERRIDE;

EXPORT_SYMBOL(boot_option_idle_override);



/*
@@ -499,7 +494,6 @@ static void poll_idle(void) 
 *

 * idle=mwait overrides this decision and forces the usage of mwait.

 */

static int __cpuinitdata force_mwait;



#define MWAIT_INFO			0x05

#define MWAIT_ECX_EXTENDED_INFO		0x01
@@ -509,7 +503,7 @@ static int __cpuinit mwait_usable(const struct cpuinfo_x86 *c) 
{

	u32 eax, ebx, ecx, edx;



	if (force_mwait)

	if (boot_option_idle_override == IDLE_FORCE_MWAIT)

		return 1;



	if (c->cpuid_level < MWAIT_INFO)
@@ -629,9 +623,10 @@ static int __init idle_setup(char *str) 
	if (!strcmp(str, "poll")) {

		printk("using polling idle threads.\n");

		pm_idle = poll_idle;

	} else if (!strcmp(str, "mwait"))

		force_mwait = 1;

	else if (!strcmp(str, "halt")) {

		boot_option_idle_override = IDLE_POLL;

	} else if (!strcmp(str, "mwait")) {

		boot_option_idle_override = IDLE_FORCE_MWAIT;

	} else if (!strcmp(str, "halt")) {

		/*

		 * When the boot option of idle=halt is added, halt is

		 * forced to be used for CPU idle. In such case CPU C2/C3
@@ -640,8 +635,7 @@ static int __init idle_setup(char *str) 
		 * the boot_option_idle_override.

		 */

		pm_idle = default_idle;

		idle_halt = 1;

		return 0;

		boot_option_idle_override = IDLE_HALT;

	} else if (!strcmp(str, "nomwait")) {

		/*

		 * If the boot option of "idle=nomwait" is added,
@@ -649,12 +643,10 @@ static int __init idle_setup(char *str) 
		 * states. In such case it won't touch the variable

		 * of boot_option_idle_override.

		 */

		idle_nomwait = 1;

		return 0;

		boot_option_idle_override = IDLE_NOMWAIT;

	} else

		return -1;



	boot_option_idle_override = 1;

	return 0;

}

early_param("idle", idle_setup);

drivers/acpi/processor_core.c

+2 −2
Original line number Diff line number Diff line
@@ -23,7 +23,7 @@ static int set_no_mwait(const struct dmi_system_id *id) 
{

	printk(KERN_NOTICE PREFIX "%s detected - "

		"disabling mwait for CPU C-states\n", id->ident);

	idle_nomwait = 1;

	boot_option_idle_override = IDLE_NOMWAIT;

	return 0;

}
@@ -283,7 +283,7 @@ acpi_processor_eval_pdc(acpi_handle handle, struct acpi_object_list *pdc_in) 
{

	acpi_status status = AE_OK;



	if (idle_nomwait) {

	if (boot_option_idle_override == IDLE_NOMWAIT) {

		/*

		 * If mwait is disabled for CPU C-states, the C2C3_FFH access

		 * mode will be disabled in the parameter of _PDC object.

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