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ACPI, intel_idle: Cleanup idle= internal variables

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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: Thomas Renninger <trenn@suse.de>
cc: x86@kernel.org
Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Thomas Renninger 2010-11-03 17:06:14 +01:00 committed by Len Brown
parent d8c216cfa5
commit d18960494f
7 changed files with 32 additions and 40 deletions
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5
arch/ia64/include/asm/processor.h
View file

@ -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__ */

6
arch/ia64/kernel/process.c
View file

@ -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);

5
arch/x86/include/asm/processor.h
View file

@ -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);

24
arch/x86/kernel/process.c
View file

@ -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);

4
drivers/acpi/processor_core.c
View file

@ -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.

24
drivers/acpi/processor_idle.c
View file

@ -79,6 +79,13 @@ module_param(bm_check_disable, uint, 0000);
static unsigned int latency_factor __read_mostly = 2;
module_param(latency_factor, uint, 0644);
static int disabled_by_idle_boot_param(void)
{
return boot_option_idle_override == IDLE_POLL ||
boot_option_idle_override == IDLE_FORCE_MWAIT ||
boot_option_idle_override == IDLE_HALT;
}
/*
* IBM ThinkPad R40e crashes mysteriously when going into C2 or C3.
* For now disable this. Probably a bug somewhere else.
@ -455,7 +462,7 @@ static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
continue;
}
if (cx.type == ACPI_STATE_C1 &&
(idle_halt || idle_nomwait)) {
(boot_option_idle_override == IDLE_NOMWAIT)) {
/*
* In most cases the C1 space_id obtained from
* _CST object is FIXED_HARDWARE access mode.
@ -1058,7 +1065,7 @@ int acpi_processor_cst_has_changed(struct acpi_processor *pr)
{
int ret = 0;
if (boot_option_idle_override)
if (disabled_by_idle_boot_param())
return 0;
if (!pr)
@ -1089,19 +1096,10 @@ int __cpuinit acpi_processor_power_init(struct acpi_processor *pr,
acpi_status status = 0;
static int first_run;
if (boot_option_idle_override)
if (disabled_by_idle_boot_param())
return 0;
if (!first_run) {
if (idle_halt) {
/*
* When the boot option of "idle=halt" is added, halt
* is used for CPU IDLE.
* In such case C2/C3 is meaningless. So the max_cstate
* is set to one.
*/
max_cstate = 1;
}
dmi_check_system(processor_power_dmi_table);
max_cstate = acpi_processor_cstate_check(max_cstate);
if (max_cstate < ACPI_C_STATES_MAX)
@ -1142,7 +1140,7 @@ int __cpuinit acpi_processor_power_init(struct acpi_processor *pr,
int acpi_processor_power_exit(struct acpi_processor *pr,
struct acpi_device *device)
{
if (boot_option_idle_override)
if (disabled_by_idle_boot_param())
return 0;
cpuidle_unregister_device(&pr->power.dev);

4
drivers/idle/intel_idle.c
View file

@ -404,6 +404,10 @@ static int __init intel_idle_init(void)
{
int retval;
/* Do not load intel_idle at all for now if idle= is passed */
if (boot_option_idle_override != IDLE_NO_OVERRIDE)
return -ENODEV;
retval = intel_idle_probe();
if (retval)
return retval;