Re: clockevents: fix resume logic

Andrew Morton
2007-09-11T11:24:29Z

On Tue, 11 Sep 2007 13:23:55 +0200 "Rafael J. Wysocki" <rjw@sisk.pl> wrote:

> On Tuesday, 11 September 2007 12:31, Andrew Morton wrote:
> > On Tue, 11 Sep 2007 11:16:04 +0200 Thomas Gleixner <tglx@linutronix.de> wrote:
> >
> > > On Tue, 2007-09-11 at 01:35 -0700, Andrew Morton wrote:
> > > > On Tue, 11 Sep 2007 01:20:05 -0700 Andrew Morton <akpm@linux-foundation.org> wrote:
> > > >
> > > > > On Tue, 11 Sep 2007 09:47:20 +0200 Thomas Gleixner <tglx@linutronix.de> wrote:
> > > > >
> > > > > > On Tue, 2007-09-11 at 09:23 +0200, Thomas Gleixner wrote:
> > > > > > > > I went back to the original patch which I sent to Linus and it matches
> > > > > > > > 18de5bc4c1f1f1fa5e14f354a7603bd6e9d4e3b6. So all I can think is that there
> > > > > > > > must have been something else in the tree which I tested which fixed the
> > > > > > > > bug which 18de5bc4c1f1f1fa5e14f354a7603bd6e9d4e3b6 introduced. argh.
> > > > > > > >
> > > > > > > > Can you think what would cause the symptoms which I described?
> > > > > > >
> > > > > > > It seems that time is not updated. Timer interrupt not active or some
> > > > > > > other odd thing. I figure out what's going on when I find a box which
> > > > > > > exposes the problem.
> > > > >
> > > > > 2.6.22-rc6-mm1's git-acpi.patch contains something which fixes this bug.
> > > >
> > > > Len's current tree fixes it too.
>
> Do you mean this one:
>
> http://git.kernel.org/?p=linux/kernel/git/lenb/linux-acpi-2.6.git

Nope.

Here's the algorthm: go to the latest -mm tree and look at the first line
of broken-out/git-acpi.patch:

GIT f94aac9883f9b02700270cf286577a9bccf98f47 git+ssh://master.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6.git#test

that gives the URL, the branch and the top-level commit. All the -mm git
trees have that first line.

Anyway, I was able to extract all the diffs and generate a patch series.
The below patch fixes current mainline on the Vaio.

It doesn't compile (natch), so there's a second hackpatch at the end which
I used to test it.

commit ef5f15a8b79123a047285ec2e3899108661df779
Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Date: Thu Feb 22 13:54:03 2007 -0800

cpuidle take2: Hookup ACPI C-states driver with cpuidle

Hookup ACPI C-states onto generic cpuidle infrastructure.

drivers/acpi/procesor_idle.c is now a ACPI C-states driver that registers as
a driver in cpuidle infrastructure and the policy part is removed from
drivers/acpi/processor_idle.c. We use governor in cpuidle instead.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Adam Belay <abelay@novell.com>
Signed-off-by: Len Brown <len.brown@intel.com>

diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
index f7de02a..7352254 100644
--- a/drivers/acpi/processor_core.c
+++ b/drivers/acpi/processor_core.c
@@ -44,6 +44,7 @@ #include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/dmi.h>
#include <linux/moduleparam.h>
+#include <linux/cpuidle.h>

#include <asm/io.h>
#include <asm/system.h>
@@ -1022,11 +1023,13 @@ #endif

acpi_processor_ppc_init();

+ cpuidle_register_driver(&acpi_idle_driver);
return 0;
}

static void __exit acpi_processor_exit(void)
{
+ cpuidle_unregister_driver(&acpi_idle_driver);

acpi_processor_ppc_exit();

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 80ffc78..0916f5e 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -40,6 +40,7 @@ #include <linux/moduleparam.h>
#include <linux/sched.h> /* need_resched() */
#include <linux/latency.h>
#include <linux/clockchips.h>
+#include <linux/cpuidle.h>

/*
* Include the apic definitions for x86 to have the APIC timer related defines
@@ -62,25 +63,15 @@ #define ACPI_PROCESSOR_CLASS
#define _COMPONENT ACPI_PROCESSOR_COMPONENT
ACPI_MODULE_NAME("processor_idle");
#define ACPI_PROCESSOR_FILE_POWER "power"
-#define US_TO_PM_TIMER_TICKS(t) ((t * (PM_TIMER_FREQUENCY/1000)) / 1000)
-#define C2_OVERHEAD 4 /* 1us (3.579 ticks per us) */
-#define C3_OVERHEAD 4 /* 1us (3.579 ticks per us) */
-static void (*pm_idle_save) (void) __read_mostly;
+#define PM_TIMER_TICKS_TO_US(p) (((p) * 1000)/(PM_TIMER_FREQUENCY/1000))
+#define C2_OVERHEAD 1 /* 1us */
+#define C3_OVERHEAD 1 /* 1us */
+
module_param(max_cstate, uint, 0644);

static unsigned int nocst __read_mostly;
module_param(nocst, uint, 0000);

-/*
- * bm_history -- bit-mask with a bit per jiffy of bus-master activity
- * 1000 HZ: 0xFFFFFFFF: 32 jiffies = 32ms
- * 800 HZ: 0xFFFFFFFF: 32 jiffies = 40ms
- * 100 HZ: 0x0000000F: 4 jiffies = 40ms
- * reduce history for more aggressive entry into C3
- */
-static unsigned int bm_history __read_mostly =
- (HZ >= 800 ? 0xFFFFFFFF : ((1U << (HZ / 25)) - 1));
-module_param(bm_history, uint, 0644);
/* --------------------------------------------------------------------------
Power Management
-------------------------------------------------------------------------- */
@@ -166,88 +157,6 @@ static struct dmi_system_id __cpuinitdat
{},
};

-static inline u32 ticks_elapsed(u32 t1, u32 t2)
-{
- if (t2 >= t1)
- return (t2 - t1);
- else if (!(acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER))
- return (((0x00FFFFFF - t1) + t2) & 0x00FFFFFF);
- else
- return ((0xFFFFFFFF - t1) + t2);
-}
-
-static void
-acpi_processor_power_activate(struct acpi_processor *pr,
- struct acpi_processor_cx *new)
-{
- struct acpi_processor_cx *old;
-
- if (!pr || !new)
- return;
-
- old = pr->power.state;
-
- if (old)
- old->promotion.count = 0;
- new->demotion.count = 0;
-
- /* Cleanup from old state. */
- if (old) {
- switch (old->type) {
- case ACPI_STATE_C3:
- /* Disable bus master reload */
- if (new->type != ACPI_STATE_C3 && pr->flags.bm_check)
- acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0);
- break;
- }
- }
-
- /* Prepare to use new state. */
- switch (new->type) {
- case ACPI_STATE_C3:
- /* Enable bus master reload */
- if (old->type != ACPI_STATE_C3 && pr->flags.bm_check)
- acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1);
- break;
- }
-
- pr->power.state = new;
-
- return;
-}
-
-static void acpi_safe_halt(void)
-{
- current_thread_info()->status &= ~TS_POLLING;
- /*
- * TS_POLLING-cleared state must be visible before we
- * test NEED_RESCHED:
- */
- smp_mb();
- if (!need_resched())
- safe_halt();
- current_thread_info()->status |= TS_POLLING;
-}
-
-static atomic_t c3_cpu_count;
-
-/* Common C-state entry for C2, C3, .. */
-static void acpi_cstate_enter(struct acpi_processor_cx *cstate)
-{
- if (cstate->space_id == ACPI_CSTATE_FFH) {
- /* Call into architectural FFH based C-state */
- acpi_processor_ffh_cstate_enter(cstate);
- } else {
- int unused;
- /* IO port based C-state */
- inb(cstate->address);
- /* Dummy wait op - must do something useless after P_LVL2 read
- because chipsets cannot guarantee that STPCLK# signal
- gets asserted in time to freeze execution properly. */
- unused = inl(acpi_gbl_FADT.xpm_timer_block.address);
- }
-}
-
#ifdef ARCH_APICTIMER_STOPS_ON_C3

/*
@@ -324,377 +233,6 @@ static void acpi_state_timer_broadcast(s

#endif

-static void acpi_processor_idle(void)
-{
- struct acpi_processor *pr = NULL;
- struct acpi_processor_cx *cx = NULL;
- struct acpi_processor_cx *next_state = NULL;
- int sleep_ticks = 0;
- u32 t1, t2 = 0;
-
- /*
- * Interrupts must be disabled during bus mastering calculations and
- * for C2/C3 transitions.
- */
- local_irq_disable();
-
- pr = processors[smp_processor_id()];
- if (!pr) {
- local_irq_enable();
- return;
- }
-
- /*
- * Check whether we truly need to go idle, or should
- * reschedule:
- */
- if (unlikely(need_resched())) {
- local_irq_enable();
- return;
- }
-
- cx = pr->power.state;
- if (!cx) {
- if (pm_idle_save)
- pm_idle_save();
- else
- acpi_safe_halt();
- return;
- }
-
- /*
- * Check BM Activity
- * -----------------
- * Check for bus mastering activity (if required), record, and check
- * for demotion.
- */
- if (pr->flags.bm_check) {
- u32 bm_status = 0;
- unsigned long diff = jiffies - pr->power.bm_check_timestamp;
-
- if (diff > 31)
- diff = 31;
-
- pr->power.bm_activity <<= diff;
-
- acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
- if (bm_status) {
- pr->power.bm_activity |= 0x1;
- acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);
- }
- /*
- * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
- * the true state of bus mastering activity; forcing us to
- * manually check the BMIDEA bit of each IDE channel.
- */
- else if (errata.piix4.bmisx) {
- if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
- || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
- pr->power.bm_activity |= 0x1;
- }
-
- pr->power.bm_check_timestamp = jiffies;
-
- /*
- * If bus mastering is or was active this jiffy, demote
- * to avoid a faulty transition. Note that the processor
- * won't enter a low-power state during this call (to this
- * function) but should upon the next.
- *
- * TBD: A better policy might be to fallback to the demotion
- * state (use it for this quantum only) istead of
- * demoting -- and rely on duration as our sole demotion
- * qualification. This may, however, introduce DMA
- * issues (e.g. floppy DMA transfer overrun/underrun).
- */
- if ((pr->power.bm_activity & 0x1) &&
- cx->demotion.threshold.bm) {
- local_irq_enable();
- next_state = cx->demotion.state;
- goto end;
- }
- }
-
-#ifdef CONFIG_HOTPLUG_CPU
- /*
- * Check for P_LVL2_UP flag before entering C2 and above on
- * an SMP system. We do it here instead of doing it at _CST/P_LVL
- * detection phase, to work cleanly with logical CPU hotplug.
- */
- if ((cx->type != ACPI_STATE_C1) && (num_online_cpus() > 1) &&
- !pr->flags.has_cst && !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
- cx = &pr->power.states[ACPI_STATE_C1];
-#endif
-
- /*
- * Sleep:
- * ------
- * Invoke the current Cx state to put the processor to sleep.
- */
- if (cx->type == ACPI_STATE_C2 || cx->type == ACPI_STATE_C3) {
- current_thread_info()->status &= ~TS_POLLING;
- /*
- * TS_POLLING-cleared state must be visible before we
- * test NEED_RESCHED:
- */
- smp_mb();
- if (need_resched()) {
- current_thread_info()->status |= TS_POLLING;
- local_irq_enable();
- return;
- }
- }
-
- switch (cx->type) {
-
- case ACPI_STATE_C1:
- /*
- * Invoke C1.
- * Use the appropriate idle routine, the one that would
- * be used without acpi C-states.
- */
- if (pm_idle_save)
- pm_idle_save();
- else
- acpi_safe_halt();
-
- /*
- * TBD: Can't get time duration while in C1, as resumes
- * go to an ISR rather than here. Need to instrument
- * base interrupt handler.
- */
- sleep_ticks = 0xFFFFFFFF;
- break;
-
- case ACPI_STATE_C2:
- /* Get start time (ticks) */
- t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
- /* Invoke C2 */
- acpi_state_timer_broadcast(pr, cx, 1);
- acpi_cstate_enter(cx);
- /* Get end time (ticks) */
- t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
-
-#ifdef CONFIG_GENERIC_TIME
- /* TSC halts in C2, so notify users */
- mark_tsc_unstable("possible TSC halt in C2");
-#endif
- /* Re-enable interrupts */
- local_irq_enable();
- current_thread_info()->status |= TS_POLLING;
- /* Compute time (ticks) that we were actually asleep */
- sleep_ticks =
- ticks_elapsed(t1, t2) - cx->latency_ticks - C2_OVERHEAD;
- acpi_state_timer_broadcast(pr, cx, 0);
- break;
-
- case ACPI_STATE_C3:
-
- if (pr->flags.bm_check) {
- if (atomic_inc_return(&c3_cpu_count) ==
- num_online_cpus()) {
- /*
- * All CPUs are trying to go to C3
- * Disable bus master arbitration
- */
- acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1);
- }
- } else {
- /* SMP with no shared cache... Invalidate cache */
- ACPI_FLUSH_CPU_CACHE();
- }
-
- /* Get start time (ticks) */
- t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
- /* Invoke C3 */
- acpi_state_timer_broadcast(pr, cx, 1);
- acpi_cstate_enter(cx);
- /* Get end time (ticks) */
- t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
- if (pr->flags.bm_check) {
- /* Enable bus master arbitration */
- atomic_dec(&c3_cpu_count);
- acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0);
- }
-
-#ifdef CONFIG_GENERIC_TIME
- /* TSC halts in C3, so notify users */
- mark_tsc_unstable("TSC halts in C3");
-#endif
- /* Re-enable interrupts */
- local_irq_enable();
- current_thread_info()->status |= TS_POLLING;
- /* Compute time (ticks) that we were actually asleep */
- sleep_ticks =
- ticks_elapsed(t1, t2) - cx->latency_ticks - C3_OVERHEAD;
- acpi_state_timer_broadcast(pr, cx, 0);
- break;
-
- default:
- local_irq_enable();
- return;
- }
- cx->usage++;
- if ((cx->type != ACPI_STATE_C1) && (sleep_ticks > 0))
- cx->time += sleep_ticks;
-
- next_state = pr->power.state;
-
-#ifdef CONFIG_HOTPLUG_CPU
- /* Don't do promotion/demotion */
- if ((cx->type == ACPI_STATE_C1) && (num_online_cpus() > 1) &&
- !pr->flags.has_cst && !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED)) {
- next_state = cx;
- goto end;
- }
-#endif
-
- /*
- * Promotion?
- * ----------
- * Track the number of longs (time asleep is greater than threshold)
- * and promote when the count threshold is reached. Note that bus
- * mastering activity may prevent promotions.
- * Do not promote above max_cstate.
- */
- if (cx->promotion.state &&
- ((cx->promotion.state - pr->power.states) <= max_cstate)) {
- if (sleep_ticks > cx->promotion.threshold.ticks &&
- cx->promotion.state->latency <= system_latency_constraint()) {
- cx->promotion.count++;
- cx->demotion.count = 0;
- if (cx->promotion.count >=
- cx->promotion.threshold.count) {
- if (pr->flags.bm_check) {
- if (!
- (pr->power.bm_activity & cx->
- promotion.threshold.bm)) {
- next_state =
- cx->promotion.state;
- goto end;
- }
- } else {
- next_state = cx->promotion.state;
- goto end;
- }
- }
- }
- }
-
- /*
- * Demotion?
- * ---------
- * Track the number of shorts (time asleep is less than time threshold)
- * and demote when the usage threshold is reached.
- */
- if (cx->demotion.state) {
- if (sleep_ticks < cx->demotion.threshold.ticks) {
- cx->demotion.count++;
- cx->promotion.count = 0;
- if (cx->demotion.count >= cx->demotion.threshold.count) {
- next_state = cx->demotion.state;
- goto end;
- }
- }
- }
-
- end:
- /*
- * Demote if current state exceeds max_cstate
- * or if the latency of the current state is unacceptable
- */
- if ((pr->power.state - pr->power.states) > max_cstate ||
- pr->power.state->latency > system_latency_constraint()) {
- if (cx->demotion.state)
- next_state = cx->demotion.state;
- }
-
- /*
- * New Cx State?
- * -------------
- * If we're going to start using a new Cx state we must clean up
- * from the previous and prepare to use the new.
- */
- if (next_state != pr->power.state)
- acpi_processor_power_activate(pr, next_state);
-}
-
-static int acpi_processor_set_power_policy(struct acpi_processor *pr)
-{
- unsigned int i;
- unsigned int state_is_set = 0;
- struct acpi_processor_cx *lower = NULL;
- struct acpi_processor_cx *higher = NULL;
- struct acpi_processor_cx *cx;
-
-
- if (!pr)
- return -EINVAL;
-
- /*
- * This function sets the default Cx state policy (OS idle handler).
- * Our scheme is to promote quickly to C2 but more conservatively
- * to C3. We're favoring C2 for its characteristics of low latency
- * (quick response), good power savings, and ability to allow bus
- * mastering activity. Note that the Cx state policy is completely
- * customizable and can be altered dynamically.
- */
-
- /* startup state */
- for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
- cx = &pr->power.states[i];
- if (!cx->valid)
- continue;
-
- if (!state_is_set)
- pr->power.state = cx;
- state_is_set++;
- break;
- }
-
- if (!state_is_set)
- return -ENODEV;
-
- /* demotion */
- for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
- cx = &pr->power.states[i];
- if (!cx->valid)
- continue;
-
- if (lower) {
- cx->demotion.state = lower;
- cx->demotion.threshold.ticks = cx->latency_ticks;
- cx->demotion.threshold.count = 1;
- if (cx->type == ACPI_STATE_C3)
- cx->demotion.threshold.bm = bm_history;
- }
-
- lower = cx;
- }
-
- /* promotion */
- for (i = (ACPI_PROCESSOR_MAX_POWER - 1); i > 0; i--) {
- cx = &pr->power.states[i];
- if (!cx->valid)
- continue;
-
- if (higher) {
- cx->promotion.state = higher;
- cx->promotion.threshold.ticks = cx->latency_ticks;
- if (cx->type >= ACPI_STATE_C2)
- cx->promotion.threshold.count = 4;
- else
- cx->promotion.threshold.count = 10;
- if (higher->type == ACPI_STATE_C3)
- cx->promotion.threshold.bm = bm_history;
- }
-
- higher = cx;
- }
-
- return 0;
-}
-
static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
{

@@ -912,7 +450,7 @@ static void acpi_processor_power_verify_
* Normalize the C2 latency to expidite policy
*/
cx->valid = 1;
- cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
+ cx->latency_ticks = cx->latency;

return;
}
@@ -986,7 +524,7 @@ static void acpi_processor_power_verify_
* use this in our C3 policy
*/
cx->valid = 1;
- cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
+ cx->latency_ticks = cx->latency;

return;
}
@@ -1052,18 +590,6 @@ static int acpi_processor_get_power_info
pr->power.count = acpi_processor_power_verify(pr);

/*
- * Set Default Policy
- * ------------------
- * Now that we know which states are supported, set the default
- * policy. Note that this policy can be changed dynamically
- * (e.g. encourage deeper sleeps to conserve battery life when
- * not on AC).
- */
- result = acpi_processor_set_power_policy(pr);
- if (result)
- return result;
-
- /*
* if one state of type C2 or C3 is available, mark this
* CPU as being "idle manageable"
*/
@@ -1080,9 +606,6 @@ static int acpi_processor_get_power_info

int acpi_processor_cst_has_changed(struct acpi_processor *pr)
{
- int result = 0;
-
-
if (!pr)
return -EINVAL;

@@ -1093,16 +616,8 @@ int acpi_processor_cst_has_changed(struc
if (!pr->flags.power_setup_done)
return -ENODEV;

- /* Fall back to the default idle loop */
- pm_idle = pm_idle_save;
- synchronize_sched(); /* Relies on interrupts forcing exit from idle. */
-
- pr->flags.power = 0;
- result = acpi_processor_get_power_info(pr);
- if ((pr->flags.power == 1) && (pr->flags.power_setup_done))
- pm_idle = acpi_processor_idle;
-
- return result;
+ acpi_processor_get_power_info(pr);
+ return cpuidle_force_redetect(&per_cpu(cpuidle_devices, pr->id));
}

/* proc interface */
@@ -1188,30 +703,6 @@ static const struct file_operations acpi
.release = single_release,
};

-#ifdef CONFIG_SMP
-static void smp_callback(void *v)
-{
- /* we already woke the CPU up, nothing more to do */
-}
-
-/*
- * This function gets called when a part of the kernel has a new latency
- * requirement. This means we need to get all processors out of their C-state,
- * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
- * wakes them all right up.
- */
-static int acpi_processor_latency_notify(struct notifier_block *b,
- unsigned long l, void *v)
-{
- smp_call_function(smp_callback, NULL, 0, 1);
- return NOTIFY_OK;
-}
-
-static struct notifier_block acpi_processor_latency_notifier = {
- .notifier_call = acpi_processor_latency_notify,
-};
-#endif
-
int __cpuinit acpi_processor_power_init(struct acpi_processor *pr,
struct acpi_device *device)
{
@@ -1228,9 +719,6 @@ int __cpuinit acpi_processor_power_init(
"ACPI: processor limited to max C-state %d\n",
max_cstate);
first_run++;
-#ifdef CONFIG_SMP
- register_latency_notifier(&acpi_processor_latency_notifier);
-#endif
}

if (!pr)
@@ -1247,6 +735,7 @@ #endif

acpi_processor_get_power_info(pr);

+
/*
* Install the idle handler if processor power management is supported.
* Note that we use previously set idle handler will be used on
@@ -1259,11 +748,6 @@ #endif
printk(" C%d[C%d]", i,
pr->power.states[i].type);
printk(")\n");
-
- if (pr->id == 0) {
- pm_idle_save = pm_idle;
- pm_idle = acpi_processor_idle;
- }
}

/* 'power' [R] */
@@ -1291,21 +775,332 @@ int acpi_processor_power_exit(struct acp
if (acpi_device_dir(device))
remove_proc_entry(ACPI_PROCESSOR_FILE_POWER,
acpi_device_dir(device));
+ return 0;
+}
+
+/**
+ * ticks_elapsed - a helper function that determines how many ticks (in US)
+ * have elapsed between two PM Timer timestamps
+ * @t1: the start time
+ * @t2: the end time
+ */
+static inline u32 ticks_elapsed(u32 t1, u32 t2)
+{
+ if (t2 >= t1)
+ return PM_TIMER_TICKS_TO_US(t2 - t1);
+ else if (!(acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER))
+ return PM_TIMER_TICKS_TO_US(((0x00FFFFFF - t1) + t2) & 0x00FFFFFF);
+ else
+ return PM_TIMER_TICKS_TO_US((0xFFFFFFFF - t1) + t2);
+}

- /* Unregister the idle handler when processor #0 is removed. */
- if (pr->id == 0) {
- pm_idle = pm_idle_save;
+/**
+ * acpi_idle_update_bm_rld - updates the BM_RLD bit depending on target state
+ * @pr: the processor
+ * @target: the new target state
+ */
+static inline void acpi_idle_update_bm_rld(struct acpi_processor *pr,
+ struct acpi_processor_cx *target)
+{
+ if (pr->flags.bm_rld_set && target->type != ACPI_STATE_C3) {
+ acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0);
+ pr->flags.bm_rld_set = 0;
+ }

- /*
- * We are about to unload the current idle thread pm callback
- * (pm_idle), Wait for all processors to update cached/local
- * copies of pm_idle before proceeding.
- */
- cpu_idle_wait();
-#ifdef CONFIG_SMP
- unregister_latency_notifier(&acpi_processor_latency_notifier);
+ if (!pr->flags.bm_rld_set && target->type == ACPI_STATE_C3) {
+ acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1);
+ pr->flags.bm_rld_set = 1;
+ }
+}
+
+/**
+ * acpi_idle_do_entry - a helper function that does C2 and C3 type entry
+ * @cx: cstate data
+ */
+static inline void acpi_idle_do_entry(struct acpi_processor_cx *cx)
+{
+ if (cx->space_id == ACPI_CSTATE_FFH) {
+ /* Call into architectural FFH based C-state */
+ acpi_processor_ffh_cstate_enter(cx);
+ } else {
+ int unused;
+ /* IO port based C-state */
+ inb(cx->address);
+ /* Dummy wait op - must do something useless after P_LVL2 read
+ because chipsets cannot guarantee that STPCLK# signal
+ gets asserted in time to freeze execution properly. */
+ unused = inl(acpi_gbl_FADT.xpm_timer_block.address);
+ }
+}
+
+/**
+ * acpi_idle_enter_c1 - enters an ACPI C1 state-type
+ * @dev: the target CPU
+ * @state: the state data
+ *
+ * This is equivalent to the HALT instruction.
+ */
+static int acpi_idle_enter_c1(struct cpuidle_device *dev,
+ struct cpuidle_state *state)
+{
+ struct acpi_processor *pr;
+ struct acpi_processor_cx *cx = cpuidle_get_statedata(state);
+ pr = processors[smp_processor_id()];
+
+ if (unlikely(!pr))
+ return 0;
+
+ if (pr->flags.bm_check)
+ acpi_idle_update_bm_rld(pr, cx);
+
+ current_thread_info()->status &= ~TS_POLLING;
+ /*
+ * TS_POLLING-cleared state must be visible before we test
+ * NEED_RESCHED:
+ */
+ smp_mb();
+ if (!need_resched())
+ safe_halt();
+ current_thread_info()->status |= TS_POLLING;
+
+ cx->usage++;
+
+ return 0;
+}
+
+/**
+ * acpi_idle_enter_c2 - enters an ACPI C2 state-type
+ * @dev: the target CPU
+ * @state: the state data
+ */
+static int acpi_idle_enter_c2(struct cpuidle_device *dev,
+ struct cpuidle_state *state)
+{
+ struct acpi_processor *pr;
+ struct acpi_processor_cx *cx = cpuidle_get_statedata(state);
+ u32 t1, t2;
+ pr = processors[smp_processor_id()];
+
+ if (unlikely(!pr))
+ return 0;
+
+ if (pr->flags.bm_check)
+ acpi_idle_update_bm_rld(pr, cx);
+
+ local_irq_disable();
+ current_thread_info()->status &= ~TS_POLLING;
+ /*
+ * TS_POLLING-cleared state must be visible before we test
+ * NEED_RESCHED:
+ */
+ smp_mb();
+
+ if (unlikely(need_resched())) {
+ current_thread_info()->status |= TS_POLLING;
+ local_irq_enable();
+ return 0;
+ }
+
+ t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
+ acpi_state_timer_broadcast(pr, cx, 1);
+ acpi_idle_do_entry(cx);
+ t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
+
+#ifdef CONFIG_GENERIC_TIME
+ /* TSC halts in C2, so notify users */
+ mark_tsc_unstable("possible TSC halt in C2");
#endif
+
+ local_irq_enable();
+ current_thread_info()->status |= TS_POLLING;
+
+ cx->usage++;
+
+ acpi_state_timer_broadcast(pr, cx, 0);
+ return ticks_elapsed(t1, t2);
+}
+
+static int c3_cpu_count;
+static DEFINE_SPINLOCK(c3_lock);
+
+/**
+ * acpi_idle_enter_c3 - enters an ACPI C3 state-type
+ * @dev: the target CPU
+ * @state: the state data
+ *
+ * Similar to C2 entry, except special bus master handling is needed.
+ */
+static int acpi_idle_enter_c3(struct cpuidle_device *dev,
+ struct cpuidle_state *state)
+{
+ struct acpi_processor *pr;
+ struct acpi_processor_cx *cx = cpuidle_get_statedata(state);
+ u32 t1, t2;
+ pr = processors[smp_processor_id()];
+
+ if (unlikely(!pr))
+ return 0;
+
+ if (pr->flags.bm_check)
+ acpi_idle_update_bm_rld(pr, cx);
+
+ local_irq_disable();
+ current_thread_info()->status &= ~TS_POLLING;
+ /*
+ * TS_POLLING-cleared state must be visible before we test
+ * NEED_RESCHED:
+ */
+ smp_mb();
+
+ if (unlikely(need_resched())) {
+ current_thread_info()->status |= TS_POLLING;
+ local_irq_enable();
+ return 0;
+ }
+
+ /* disable bus master */
+ if (pr->flags.bm_check) {
+ spin_lock(&c3_lock);
+ c3_cpu_count++;
+ if (c3_cpu_count == num_online_cpus()) {
+ /*
+ * All CPUs are trying to go to C3
+ * Disable bus master arbitration
+ */
+ acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1);
+ }
+ spin_unlock(&c3_lock);
+ } else {
+ /* SMP with no shared cache... Invalidate cache */
+ ACPI_FLUSH_CPU_CACHE();
+ }
+
+ /* Get start time (ticks) */
+ t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
+ acpi_state_timer_broadcast(pr, cx, 1);
+ acpi_idle_do_entry(cx);
+ t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
+
+ if (pr->flags.bm_check) {
+ spin_lock(&c3_lock);
+ /* Enable bus master arbitration */
+ if (c3_cpu_count == num_online_cpus())
+ acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0);
+ c3_cpu_count--;
+ spin_unlock(&c3_lock);
}

+#ifdef CONFIG_GENERIC_TIME
+ /* TSC halts in C3, so notify users */
+ mark_tsc_unstable("TSC halts in C3");
+#endif
+
+ local_irq_enable();
+ current_thread_info()->status |= TS_POLLING;
+
+ cx->usage++;
+
+ acpi_state_timer_broadcast(pr, cx, 0);
+ return ticks_elapsed(t1, t2);
+}
+
+/**
+ * acpi_idle_bm_check - checks if bus master activity was detected
+ */
+static int acpi_idle_bm_check(void)
+{
+ u32 bm_status = 0;
+
+ acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
+ if (bm_status)
+ acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);
+ /*
+ * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
+ * the true state of bus mastering activity; forcing us to
+ * manually check the BMIDEA bit of each IDE channel.
+ */
+ else if (errata.piix4.bmisx) {
+ if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
+ || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
+ bm_status = 1;
+ }
+ return bm_status;
+}
+
+/**
+ * acpi_idle_init - attaches the driver to a CPU
+ * @dev: the CPU
+ */
+static int acpi_idle_init(struct cpuidle_device *dev)
+{
+ int cpu = dev->cpu;
+ int i, count = 0;
+ struct acpi_processor_cx *cx;
+ struct cpuidle_state *state;
+
+ struct acpi_processor *pr = processors[cpu];
+
+ if (!pr->flags.power_setup_done)
+ return -EINVAL;
+
+ if (pr->flags.power == 0) {
+ return -EINVAL;
+ }
+
+ for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
+ cx = &pr->power.states[i];
+ state = &dev->states[count];
+
+ if (!cx->valid)
+ continue;
+
+#ifdef CONFIG_HOTPLUG_CPU
+ if ((cx->type != ACPI_STATE_C1) && (num_online_cpus() > 1) &&
+ !pr->flags.has_cst &&
+ !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
+ continue;
+#endif
+ cpuidle_set_statedata(state, cx);
+
+ state->exit_latency = cx->latency;
+ state->target_residency = cx->latency * 6;
+ state->power_usage = cx->power;
+
+ state->flags = 0;
+ switch (cx->type) {
+ case ACPI_STATE_C1:
+ state->flags |= CPUIDLE_FLAG_SHALLOW;
+ state->enter = acpi_idle_enter_c1;
+ break;
+
+ case ACPI_STATE_C2:
+ state->flags |= CPUIDLE_FLAG_BALANCED;
+ state->flags |= CPUIDLE_FLAG_TIME_VALID;
+ state->enter = acpi_idle_enter_c2;
+ break;
+
+ case ACPI_STATE_C3:
+ state->flags |= CPUIDLE_FLAG_DEEP;
+ state->flags |= CPUIDLE_FLAG_TIME_VALID;
+ state->flags |= CPUIDLE_FLAG_CHECK_BM;
+ state->enter = acpi_idle_enter_c3;
+ break;
+ }
+
+ count++;
+ }
+
+ if (!count)
+ return -EINVAL;
+
+ dev->state_count = count;
return 0;
}
+
+struct cpuidle_driver acpi_idle_driver = {
+ .name = "acpi_idle",
+ .init = acpi_idle_init,
+ .redetect = acpi_idle_init,
+ .bm_check = acpi_idle_bm_check,
+ .owner = THIS_MODULE,
+};
diff --git a/include/acpi/processor.h b/include/acpi/processor.h
index b4b0ffd..dcd6aca 100644
--- a/include/acpi/processor.h
+++ b/include/acpi/processor.h
@@ -161,6 +161,7 @@ struct acpi_processor_flags {
u8 bm_check:1;
u8 has_cst:1;
u8 power_setup_done:1;
+ u8 bm_rld_set:1;
};

struct acpi_processor {
@@ -279,6 +280,7 @@ int acpi_processor_power_init(struct acp
int acpi_processor_cst_has_changed(struct acpi_processor *pr);
int acpi_processor_power_exit(struct acpi_processor *pr,
struct acpi_device *device);
+extern struct cpuidle_driver acpi_idle_driver;

/* in processor_thermal.c */
int acpi_processor_get_limit_info(struct acpi_processor *pr);

hackpatch:

acpi/processor.h | 0
drivers/acpi/processor_core.c | 4 ++--
drivers/acpi/processor_idle.c | 2 +-
3 files changed, 3 insertions(+), 3 deletions(-)

diff -puN drivers/acpi/processor_core.c~ef5f15a8b79123a047285ec2e3899108661df779-fix drivers/acpi/processor_core.c
--- a/drivers/acpi/processor_core.c~ef5f15a8b79123a047285ec2e3899108661df779-fix
+++ a/drivers/acpi/processor_core.c
@@ -1039,13 +1039,13 @@ static int __init acpi_processor_init(vo

acpi_processor_ppc_init();

- cpuidle_register_driver(&acpi_idle_driver);
+// cpuidle_register_driver(&acpi_idle_driver);
return 0;
}

static void __exit acpi_processor_exit(void)
{
- cpuidle_unregister_driver(&acpi_idle_driver);
+// cpuidle_unregister_driver(&acpi_idle_driver);

acpi_processor_ppc_exit();

diff -puN drivers/acpi/processor_idle.c~ef5f15a8b79123a047285ec2e3899108661df779-fix drivers/acpi/processor_idle.c
--- a/drivers/acpi/processor_idle.c~ef5f15a8b79123a047285ec2e3899108661df779-fix
+++ a/drivers/acpi/processor_idle.c
@@ -633,7 +633,7 @@ int acpi_processor_cst_has_changed(struc
return -ENODEV;

acpi_processor_get_power_info(pr);
- return cpuidle_force_redetect(&per_cpu(cpuidle_devices, pr->id));
+ return 0;
}

/* proc interface */
diff -puN include/acpi/processor.h~ef5f15a8b79123a047285ec2e3899108661df779-fix include/acpi/processor.h
_