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Message-Id: <200708291722.47688.rjw@sisk.pl>
Date: Wed, 29 Aug 2007 17:22:46 +0200
From: "Rafael J. Wysocki" <rjw@...k.pl>
To: Len Brown <lenb@...nel.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>, Pavel Machek <pavel@....cz>,
pm list <linux-pm@...ts.linux-foundation.org>,
"Moore, Robert" <robert.moore@...el.com>
Subject: Re: [PATCH -mm 2/3] PM: More fine grained ACPI handling during suspend and hibernation (rev. 3)
On Tuesday, 28 August 2007 23:35, Rafael J. Wysocki wrote:
> On Tuesday, 28 August 2007 21:48, Len Brown wrote:
> > On Monday 27 August 2007 17:51, Rafael J. Wysocki wrote:
> > > According to the ACPI specification (eg. ACPI 2.0c, sec. 7.3.1, 7.3.3,
> > > ACPI 3.0b, sec. 7.3.1, 7.3.3) the _GTS and _BFS global control methods should
> > > be executed, respectively, right before entering a sleep state (S1-S4) and right
> > > after leaving it, but we don't follow this reqirement. Namely, in our
> > > implementation the nonboot CPUs are disabled after executing _GTS and enabled
> > > before executing _BFS, which doesn't seem to be correct.
> >
> > I've never encountered a BIOS that actually implements _GTS or _BFS,
> > so I expect that changing how they are invoked may be somewhat academic.
>
> It is for now, but once we have a system that implements them, we'd most
> probably need to change the current code, so I think it's better to consider
> that in advance.
>
> > > [In fact, the ACPI
> > > specification requires that no physical I/O and interrupt servicing be performed
> > > after the sleep state has been left and before _BFS is executed as well as after
> > > executing _GTS and before the sleep state is entered, but we can't follow this
> > > requirement literally,
> >
> > > since our AML interpreter needs to run with interrupts
> > > enabled and we need to carry out some operations with interrupts disabled before
> > > entering the sleep state and after leaving it.]
> >
> > This is sort of a myth.
> >
> > The real requirement is that the ACPI interpreter must be able to call kmalloc().
> > It does this today via acpi_os_allocate(), which does this:
> >
> > kmalloc(size, irqs_disabled()? GFP_ATOMIC : GFP_KERNEL);
> >
> > No, we don't actually run the interpreter during device interrupts,
> > but we need to be able to run it with interrupts off for boot,
> > suspend, and resume.
>
> At present, during suspend and resume we always call the AML interpreter
> with interrupts enabled.
>
> Frankly, I'd like _BFS and _GTS to be executed with interrupts disabled,
> just as the specification tells us to do. If you think that's safe, I'll
> change the patch to work this way.
Appended is an alternative version of the $subject patch, in which the _GTS and
_BFS methods are executed with interrupts disabled. It is simpler than the
previous one, so I prefer it. :-)
Greetings,
Rafael
---
From: Rafael J. Wysocki <rjw@...k.pl>
According to the ACPI specification (eg. ACPI 2.0c, sec. 7.3.1, 7.3.3,
ACPI 3.0b, sec. 7.3.1, 7.3.3) the _GTS and _BFS global control methods should
be executed, respectively, right before entering a sleep state (S1-S4) and right
after leaving it, but we don't follow this reqirement. Namely, in our
implementation the nonboot CPUs are disabled after executing _GTS and enabled
before executing _BFS, which doesn't seem to be correct. Moreover,
acpi_enable() called after restoring the system memory state from a hibernation
image should really be executed before enabling the nonboot CPUs, since
functional ACPI layer may be needed for that. Thus, it seems reasonable to do
the following changes:
* Move the execution of _GTS from acpi_enter_sleep_state_prep() to
acpi_enter_sleep_state()
* Move the execution of _BFS to before the execution of _SST in
acpi_leave_sleep_state()
* Move the enabling of GPS, the execution of _WAK and the enabling of power
buttons from acpi_leave_sleep_state() to a new function
acpi_leave_sleep_state_finish()
* Make acpi_leave_sleep_state() be called with interrupts disabled from
acpi_pm_enter(), right after leaving the sleep state
* Make acpi_pm_finish() call acpi_leave_sleep_state_finish() instead of
acpi_leave_sleep_state()
* Introduce a new global hibernation callback ->leave() to be executed with
interrupts disabled just after transferring control from the boot kernel to
the image kernel and make it call acpi_enable() and
acpi_leave_sleep_state(ACPI_STATE_S4) on ACPI systems
* Make acpi_hibernation_finish() call acpi_leave_sleep_state_finish() instead of
acpi_leave_sleep_state()
Signed-off-by: Rafael J. Wysocki <rjw@...k.pl>
---
drivers/acpi/hardware/hwsleep.c | 73 +++++++++++++++++++++++++++++++---------
drivers/acpi/sleep/main.c | 13 ++++++-
include/acpi/acpixf.h | 2 +
include/linux/suspend.h | 7 +++
kernel/power/disk.c | 62 ++++++++++++++++++++++++++++++++-
kernel/power/power.h | 1
kernel/power/swsusp.c | 33 ------------------
7 files changed, 137 insertions(+), 54 deletions(-)
Index: linux-2.6.23-rc4/drivers/acpi/hardware/hwsleep.c
===================================================================
--- linux-2.6.23-rc4.orig/drivers/acpi/hardware/hwsleep.c
+++ linux-2.6.23-rc4/drivers/acpi/hardware/hwsleep.c
@@ -192,18 +192,13 @@ acpi_status acpi_enter_sleep_state_prep(
arg.type = ACPI_TYPE_INTEGER;
arg.integer.value = sleep_state;
- /* Run the _PTS and _GTS methods */
+ /* Run the _PTS method */
status = acpi_evaluate_object(NULL, METHOD_NAME__PTS, &arg_list, NULL);
if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
return_ACPI_STATUS(status);
}
- status = acpi_evaluate_object(NULL, METHOD_NAME__GTS, &arg_list, NULL);
- if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
- return_ACPI_STATUS(status);
- }
-
/* Setup the argument to _SST */
switch (sleep_state) {
@@ -263,6 +258,8 @@ acpi_status asmlinkage acpi_enter_sleep_
struct acpi_bit_register_info *sleep_enable_reg_info;
u32 in_value;
acpi_status status;
+ struct acpi_object_list arg_list;
+ union acpi_object arg;
ACPI_FUNCTION_TRACE(acpi_enter_sleep_state);
@@ -317,6 +314,19 @@ acpi_status asmlinkage acpi_enter_sleep_
ACPI_DEBUG_PRINT((ACPI_DB_INIT,
"Entering sleep state [S%d]\n", sleep_state));
+ /* Execute the _GTS method */
+
+ arg_list.count = 1;
+ arg_list.pointer = &arg;
+
+ arg.type = ACPI_TYPE_INTEGER;
+ arg.integer.value = sleep_state;
+
+ status = acpi_evaluate_object(NULL, METHOD_NAME__GTS, &arg_list, NULL);
+ if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
+ return_ACPI_STATUS(status);
+ }
+
/* Clear SLP_EN and SLP_TYP fields */
PM1Acontrol &= ~(sleep_type_reg_info->access_bit_mask |
@@ -484,8 +494,9 @@ ACPI_EXPORT_SYMBOL(acpi_enter_sleep_stat
*
* RETURN: Status
*
- * DESCRIPTION: Perform OS-independent ACPI cleanup after a sleep
- * Called with interrupts ENABLED.
+ * DESCRIPTION: Perform the first stage of OS-independent ACPI cleanup after a
+ * sleep.
+ * Called with one CPU on line and with interrupts DISABLED.
*
******************************************************************************/
acpi_status acpi_leave_sleep_state(u8 sleep_state)
@@ -560,17 +571,43 @@ acpi_status acpi_leave_sleep_state(u8 sl
/* Ignore any errors from these methods */
+ arg.integer.value = sleep_state;
+ status = acpi_evaluate_object(NULL, METHOD_NAME__BFS, &arg_list, NULL);
+ if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
+ ACPI_EXCEPTION((AE_INFO, status, "During Method _BFS"));
+ }
+
arg.integer.value = ACPI_SST_WAKING;
status = acpi_evaluate_object(NULL, METHOD_NAME__SST, &arg_list, NULL);
if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
ACPI_EXCEPTION((AE_INFO, status, "During Method _SST"));
}
- arg.integer.value = sleep_state;
- status = acpi_evaluate_object(NULL, METHOD_NAME__BFS, &arg_list, NULL);
- if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
- ACPI_EXCEPTION((AE_INFO, status, "During Method _BFS"));
- }
+ return_ACPI_STATUS(AE_OK);
+}
+
+ACPI_EXPORT_SYMBOL(acpi_leave_sleep_state)
+
+/*******************************************************************************
+ *
+ * FUNCTION: acpi_leave_sleep_state_finish
+ *
+ * PARAMETERS: sleep_state - Which sleep state we just exited
+ *
+ * RETURN: Status
+ *
+ * DESCRIPTION: Perform the second stage of OS-independent ACPI cleanup after a
+ * sleep.
+ * Called with interrupts ENABLED.
+ *
+ ******************************************************************************/
+acpi_status acpi_leave_sleep_state_finish(u8 sleep_state)
+{
+ struct acpi_object_list arg_list;
+ union acpi_object arg;
+ acpi_status status;
+
+ ACPI_FUNCTION_TRACE(acpi_leave_sleep_state_finish);
/*
* GPEs must be enabled before _WAK is called as GPEs
@@ -589,6 +626,14 @@ acpi_status acpi_leave_sleep_state(u8 sl
return_ACPI_STATUS(status);
}
+ /* Execute the _WAK method */
+
+ arg_list.count = 1;
+ arg_list.pointer = &arg;
+
+ arg.type = ACPI_TYPE_INTEGER;
+ arg.integer.value = sleep_state;
+
status = acpi_evaluate_object(NULL, METHOD_NAME__WAK, &arg_list, NULL);
if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
ACPI_EXCEPTION((AE_INFO, status, "During Method _WAK"));
@@ -615,5 +660,3 @@ acpi_status acpi_leave_sleep_state(u8 sl
return_ACPI_STATUS(status);
}
-
-ACPI_EXPORT_SYMBOL(acpi_leave_sleep_state)
Index: linux-2.6.23-rc4/include/acpi/acpixf.h
===================================================================
--- linux-2.6.23-rc4.orig/include/acpi/acpixf.h
+++ linux-2.6.23-rc4/include/acpi/acpixf.h
@@ -335,4 +335,6 @@ acpi_status asmlinkage acpi_enter_sleep_
acpi_status acpi_leave_sleep_state(u8 sleep_state);
+acpi_status acpi_leave_sleep_state_finish(u8 sleep_state);
+
#endif /* __ACXFACE_H__ */
Index: linux-2.6.23-rc4/include/linux/suspend.h
===================================================================
--- linux-2.6.23-rc4.orig/include/linux/suspend.h
+++ linux-2.6.23-rc4/include/linux/suspend.h
@@ -156,6 +156,12 @@ extern void mark_free_pages(struct zone
* Called after the nonboot CPUs have been disabled and all of the low
* level devices have been shut down (runs with IRQs off).
*
+ * @leave: Perform the first stage of the cleanup after the system sleep state
+ * indicated by @set_target() has been left.
+ * Called right after contol has been passed from the boot kernel to the
+ * image kernel, before the nonboot CPUs are enabled and before devices are
+ * resumed. Executed with interrupts disabled.
+ *
* @pre_restore: Prepare system for the restoration from a hibernation image.
* Called right after devices have been frozen and before the nonboot
* CPUs are disabled (runs with IRQs on).
@@ -170,6 +176,7 @@ struct platform_hibernation_ops {
void (*finish)(void);
int (*prepare)(void);
int (*enter)(void);
+ void (*leave)(void);
int (*pre_restore)(void);
void (*restore_cleanup)(void);
};
Index: linux-2.6.23-rc4/kernel/power/disk.c
===================================================================
--- linux-2.6.23-rc4.orig/kernel/power/disk.c
+++ linux-2.6.23-rc4/kernel/power/disk.c
@@ -55,7 +55,7 @@ static struct platform_hibernation_ops *
void hibernation_set_ops(struct platform_hibernation_ops *ops)
{
if (ops && !(ops->start && ops->pre_snapshot && ops->finish
- && ops->prepare && ops->enter && ops->pre_restore
+ && ops->prepare && ops->enter && ops->leave && ops->pre_restore
&& ops->restore_cleanup)) {
WARN_ON(1);
return;
@@ -93,8 +93,19 @@ static int platform_pre_snapshot(int pla
}
/**
+ * platform_leave - prepare the machine for switching to the normal mode
+ * of operation using the platform driver (called with interrupts disabled)
+ */
+
+static void platform_leave(int platform_mode)
+{
+ if (platform_mode && hibernation_ops)
+ hibernation_ops->leave();
+}
+
+/**
* platform_finish - switch the machine to the normal mode of operation
- * using the platform driver (must be called after platform_prepare())
+ * using the platform driver (must be called after platform_leave())
*/
static void platform_finish(int platform_mode)
@@ -129,6 +140,51 @@ static void platform_restore_cleanup(int
}
/**
+ * create_image - freeze devices that need to be frozen with interrupts
+ * off, create the hibernation image and thaw those devices. Control
+ * reappears in this routine after a restore.
+ */
+
+int create_image(int platform_mode)
+{
+ int error;
+
+ error = arch_prepare_suspend();
+ if (error)
+ return error;
+
+ local_irq_disable();
+ /* At this point, device_suspend() has been called, but *not*
+ * device_power_down(). We *must* call device_power_down() now.
+ * Otherwise, drivers for some devices (e.g. interrupt controllers)
+ * become desynchronized with the actual state of the hardware
+ * at resume time, and evil weirdness ensues.
+ */
+ error = device_power_down(PMSG_FREEZE);
+ if (error) {
+ printk(KERN_ERR "Some devices failed to power down, "
+ KERN_ERR "aborting suspend\n");
+ goto Enable_irqs;
+ }
+
+ save_processor_state();
+ error = swsusp_arch_suspend();
+ if (error)
+ printk(KERN_ERR "Error %d while creating the image\n", error);
+ /* Restore control flow magically appears here */
+ restore_processor_state();
+ if (!error && !in_suspend)
+ platform_leave(platform_mode);
+ /* NOTE: device_power_up() is just a resume() for devices
+ * that suspended with irqs off ... no overall powerup.
+ */
+ device_power_up();
+ Enable_irqs:
+ local_irq_enable();
+ return error;
+}
+
+/**
* hibernation_snapshot - quiesce devices and create the hibernation
* snapshot image.
* @platform_mode - if set, use the platform driver, if available, to
@@ -163,7 +219,7 @@ int hibernation_snapshot(int platform_mo
if (!error) {
if (hibernation_mode != HIBERNATION_TEST) {
in_suspend = 1;
- error = swsusp_suspend();
+ error = create_image(platform_mode);
/* Control returns here after successful restore */
} else {
printk("swsusp debug: Waiting for 5 seconds.\n");
Index: linux-2.6.23-rc4/kernel/power/swsusp.c
===================================================================
--- linux-2.6.23-rc4.orig/kernel/power/swsusp.c
+++ linux-2.6.23-rc4/kernel/power/swsusp.c
@@ -270,39 +270,6 @@ int swsusp_shrink_memory(void)
return 0;
}
-int swsusp_suspend(void)
-{
- int error;
-
- if ((error = arch_prepare_suspend()))
- return error;
-
- local_irq_disable();
- /* At this point, device_suspend() has been called, but *not*
- * device_power_down(). We *must* device_power_down() now.
- * Otherwise, drivers for some devices (e.g. interrupt controllers)
- * become desynchronized with the actual state of the hardware
- * at resume time, and evil weirdness ensues.
- */
- if ((error = device_power_down(PMSG_FREEZE))) {
- printk(KERN_ERR "Some devices failed to power down, aborting suspend\n");
- goto Enable_irqs;
- }
-
- save_processor_state();
- if ((error = swsusp_arch_suspend()))
- printk(KERN_ERR "Error %d suspending\n", error);
- /* Restore control flow magically appears here */
- restore_processor_state();
- /* NOTE: device_power_up() is just a resume() for devices
- * that suspended with irqs off ... no overall powerup.
- */
- device_power_up();
- Enable_irqs:
- local_irq_enable();
- return error;
-}
-
int swsusp_resume(void)
{
int error;
Index: linux-2.6.23-rc4/kernel/power/power.h
===================================================================
--- linux-2.6.23-rc4.orig/kernel/power/power.h
+++ linux-2.6.23-rc4/kernel/power/power.h
@@ -183,7 +183,6 @@ extern int swsusp_swap_in_use(void);
extern int swsusp_check(void);
extern int swsusp_shrink_memory(void);
extern void swsusp_free(void);
-extern int swsusp_suspend(void);
extern int swsusp_resume(void);
extern int swsusp_read(unsigned int *flags_p);
extern int swsusp_write(unsigned int flags);
Index: linux-2.6.23-rc4/drivers/acpi/sleep/main.c
===================================================================
--- linux-2.6.23-rc4.orig/drivers/acpi/sleep/main.c
+++ linux-2.6.23-rc4/drivers/acpi/sleep/main.c
@@ -114,6 +114,9 @@ static int acpi_pm_enter(suspend_state_t
break;
}
+ /* Execute _BFS */
+ acpi_leave_sleep_state(acpi_state);
+
/* ACPI 3.0 specs (P62) says that it's the responsabilty
* of the OSPM to clear the status bit [ implying that the
* POWER_BUTTON event should not reach userspace ]
@@ -149,7 +152,7 @@ static void acpi_pm_finish(void)
{
u32 acpi_state = acpi_target_sleep_state;
- acpi_leave_sleep_state(acpi_state);
+ acpi_leave_sleep_state_finish(acpi_state);
acpi_disable_wakeup_device(acpi_state);
/* reset firmware waking vector */
@@ -238,7 +241,7 @@ static int acpi_hibernation_enter(void)
return ACPI_SUCCESS(status) ? 0 : -EFAULT;
}
-static void acpi_hibernation_finish(void)
+static void acpi_hibernation_leave(void)
{
/*
* If ACPI is not enabled by the BIOS and the boot kernel, we need to
@@ -246,6 +249,11 @@ static void acpi_hibernation_finish(void
*/
acpi_enable();
acpi_leave_sleep_state(ACPI_STATE_S4);
+}
+
+static void acpi_hibernation_finish(void)
+{
+ acpi_leave_sleep_state_finish(ACPI_STATE_S4);
acpi_disable_wakeup_device(ACPI_STATE_S4);
/* reset firmware waking vector */
@@ -274,6 +282,7 @@ static struct platform_hibernation_ops a
.finish = acpi_hibernation_finish,
.prepare = acpi_hibernation_prepare,
.enter = acpi_hibernation_enter,
+ .leave = acpi_hibernation_leave,
.pre_restore = acpi_hibernation_pre_restore,
.restore_cleanup = acpi_hibernation_restore_cleanup,
};
-
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