[RFC][PATCH 2/2] ACPI PM: Add possibility to change suspend sequence

["Rafael J. Wysocki" <rjw@sisk.pl>]

From: Rafael J. Wysocki <rjw@sisk.pl>

There are some systems out there that don't work correctly with
our current suspend/hibernation code ordering.  Provide a workaround
for these systems allowing them to pass the
'acpi_old_suspend_ordering' command line parameter to the kernel that
will make it use the pre-ACPI 2.0 suspend code ordering.

Unfortunately, that requires us to add a platform hook to the
resuming of devices for recovering the platform in case one of the
device drivers' .suspend() routines returns error code.  Namely,
ACPI 1.0 specifies that _PTS should be called before suspending
devices, but _WAK still should be called before resuming them in
order to undo the changes made by _PTS.  However, if there is an
error during suspending devices, they are automatically resumed
without returning control to the PM core, so the _WAK has to be
called from within device_resume() in that cases.

The patch also reorders and refactors the ACPI suspend/hibernation
code to avoid duplication as far as reasonably possible.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
 Documentation/kernel-parameters.txt |    5 
 drivers/acpi/sleep/main.c           |  278 +++++++++++++++++++++---------------
 drivers/base/power/main.c           |    2 
 include/linux/suspend.h             |   14 +
 kernel/power/disk.c                 |   28 ++-
 kernel/power/main.c                 |    9 -
 6 files changed, 212 insertions(+), 124 deletions(-)

Index: linux-2.6/Documentation/kernel-parameters.txt
===================================================================
--- linux-2.6.orig/Documentation/kernel-parameters.txt
+++ linux-2.6/Documentation/kernel-parameters.txt
@@ -157,6 +157,11 @@ and is between 256 and 4096 characters. 
 			default: The hardware signature is checked during
 			         resume from S4.
 
+	acpi_old_suspend_ordering [HW,ACPI] ACPI suspend ordering
+			Enforce the ACPI 1.0 ordering of the _PTS control
+			method wrt putting devices into low power states
+			default: ACPI 2.0 ordering of _PTS
+
 	acpi_sci=	[HW,ACPI] ACPI System Control Interrupt trigger mode
 			Format: { level | edge | high | low }
 
Index: linux-2.6/drivers/acpi/sleep/main.c
===================================================================
--- linux-2.6.orig/drivers/acpi/sleep/main.c
+++ linux-2.6/drivers/acpi/sleep/main.c
@@ -24,10 +24,6 @@
 
 u8 sleep_states[ACPI_S_STATE_COUNT];
 
-#ifdef CONFIG_PM_SLEEP
-static u32 acpi_target_sleep_state = ACPI_STATE_S0;
-#endif
-
 static int acpi_sleep_prepare(u32 acpi_state)
 {
 #ifdef CONFIG_ACPI_SLEEP
@@ -50,9 +46,98 @@ static int acpi_sleep_prepare(u32 acpi_s
 	return 0;
 }
 
-#ifdef CONFIG_SUSPEND
-static struct platform_suspend_ops acpi_suspend_ops;
+#ifdef CONFIG_PM_SLEEP
+static u32 acpi_target_sleep_state = ACPI_STATE_S0;
+
+/*
+ * ACPI 1.0 wants us to execute _PTS before suspending devices, so we allow the
+ * user to request that behavior by using the 'acpi_old_suspend_ordering'
+ * kernel command line option that causes the following variable to be set.
+ */
+static bool old_suspend_ordering;
 
+static int __init acpi_old_suspend_ordering(char *str)
+{
+	old_suspend_ordering = true;
+	return 1;
+}
+__setup("acpi_old_suspend_ordering", acpi_old_suspend_ordering);
+
+/**
+ *	acpi_pm_disable_gpes - Disable the GPEs.
+ */
+static int acpi_pm_disable_gpes(void)
+{
+	acpi_hw_disable_all_gpes();
+	return 0;
+}
+
+/**
+ *	__acpi_pm_prepare - Prepare the platform to enter the target state.
+ *
+ *	If necessary, set the firmware waking vector and do arch-specific
+ *	nastiness to get the wakeup code to the waking vector.
+ */
+static int __acpi_pm_prepare(void)
+{
+	int error = acpi_sleep_prepare(acpi_target_sleep_state);
+
+	if (error)
+		acpi_target_sleep_state = ACPI_STATE_S0;
+	return error;
+}
+
+/**
+ *	acpi_pm_prepare - Prepare the platform to enter the target sleep
+ *		state and disable the GPEs.
+ */
+static int acpi_pm_prepare(void)
+{
+	int error = __acpi_pm_prepare();
+
+	if (!error)
+		acpi_hw_disable_all_gpes();
+	return error;
+}
+
+/**
+ *	acpi_pm_finish - Instruct the platform to leave a sleep state.
+ *
+ *	This is called after we wake back up (or if entering the sleep state
+ *	failed).
+ */
+static void acpi_pm_finish(void)
+{
+	u32 acpi_state = acpi_target_sleep_state;
+
+	if (acpi_state == ACPI_STATE_S0)
+		return;
+
+	printk(KERN_INFO PREFIX "Waking up from system sleep state S%d\n",
+		acpi_state);
+	acpi_disable_wakeup_device(acpi_state);
+	acpi_leave_sleep_state(acpi_state);
+
+	/* reset firmware waking vector */
+	acpi_set_firmware_waking_vector((acpi_physical_address) 0);
+
+	acpi_target_sleep_state = ACPI_STATE_S0;
+}
+
+/**
+ *	acpi_pm_end - Finish up suspend sequence.
+ */
+static void acpi_pm_end(void)
+{
+	/*
+	 * This is necessary in case acpi_pm_finish() is not called during a
+	 * failing transition to a sleep state.
+	 */
+	acpi_target_sleep_state = ACPI_STATE_S0;
+}
+#endif /* CONFIG_PM_SLEEP */
+
+#ifdef CONFIG_SUSPEND
 extern void do_suspend_lowlevel(void);
 
 static u32 acpi_suspend_states[] = {
@@ -66,7 +151,6 @@ static u32 acpi_suspend_states[] = {
  *	acpi_suspend_begin - Set the target system sleep state to the state
  *		associated with given @pm_state, if supported.
  */
-
 static int acpi_suspend_begin(suspend_state_t pm_state)
 {
 	u32 acpi_state = acpi_suspend_states[pm_state];
@@ -83,25 +167,6 @@ static int acpi_suspend_begin(suspend_st
 }
 
 /**
- *	acpi_suspend_prepare - Do preliminary suspend work.
- *
- *	If necessary, set the firmware waking vector and do arch-specific
- *	nastiness to get the wakeup code to the waking vector.
- */
-
-static int acpi_suspend_prepare(void)
-{
-	int error = acpi_sleep_prepare(acpi_target_sleep_state);
-
-	if (error) {
-		acpi_target_sleep_state = ACPI_STATE_S0;
-		return error;
-	}
-
-	return ACPI_SUCCESS(acpi_hw_disable_all_gpes()) ? 0 : -EFAULT;
-}
-
-/**
  *	acpi_suspend_enter - Actually enter a sleep state.
  *	@pm_state: ignored
  *
@@ -109,7 +174,6 @@ static int acpi_suspend_prepare(void)
  *	assembly, which in turn call acpi_enter_sleep_state().
  *	It's unfortunate, but it works. Please fix if you're feeling frisky.
  */
-
 static int acpi_suspend_enter(suspend_state_t pm_state)
 {
 	acpi_status status = AE_OK;
@@ -166,39 +230,6 @@ static int acpi_suspend_enter(suspend_st
 	return ACPI_SUCCESS(status) ? 0 : -EFAULT;
 }
 
-/**
- *	acpi_suspend_finish - Instruct the platform to leave a sleep state.
- *
- *	This is called after we wake back up (or if entering the sleep state
- *	failed). 
- */
-
-static void acpi_suspend_finish(void)
-{
-	u32 acpi_state = acpi_target_sleep_state;
-
-	acpi_disable_wakeup_device(acpi_state);
-	acpi_leave_sleep_state(acpi_state);
-
-	/* reset firmware waking vector */
-	acpi_set_firmware_waking_vector((acpi_physical_address) 0);
-
-	acpi_target_sleep_state = ACPI_STATE_S0;
-}
-
-/**
- *	acpi_suspend_end - Finish up suspend sequence.
- */
-
-static void acpi_suspend_end(void)
-{
-	/*
-	 * This is necessary in case acpi_suspend_finish() is not called during a
-	 * failing transition to a sleep state.
-	 */
-	acpi_target_sleep_state = ACPI_STATE_S0;
-}
-
 static int acpi_suspend_state_valid(suspend_state_t pm_state)
 {
 	u32 acpi_state;
@@ -218,10 +249,39 @@ static int acpi_suspend_state_valid(susp
 static struct platform_suspend_ops acpi_suspend_ops = {
 	.valid = acpi_suspend_state_valid,
 	.begin = acpi_suspend_begin,
-	.prepare = acpi_suspend_prepare,
+	.prepare = acpi_pm_prepare,
+	.enter = acpi_suspend_enter,
+	.finish = acpi_pm_finish,
+	.end = acpi_pm_end,
+};
+
+/**
+ *	acpi_suspend_begin_old - Set the target system sleep state to the
+ *		state associated with given @pm_state, if supported, and
+ *		execute the _PTS control method.  This function is used if the
+ *		pre-ACPI 2.0 suspend ordering has been requested.
+ */
+static int acpi_suspend_begin_old(suspend_state_t pm_state)
+{
+	int error = acpi_suspend_begin(pm_state);
+
+	if (!error)
+		error = __acpi_pm_prepare();
+	return error;
+}
+
+/*
+ * The following callbacks are used if the pre-ACPI 2.0 suspend ordering has
+ * been requested.
+ */
+static struct platform_suspend_ops acpi_suspend_ops_old = {
+	.valid = acpi_suspend_state_valid,
+	.begin = acpi_suspend_begin_old,
+	.prepare = acpi_pm_disable_gpes,
 	.enter = acpi_suspend_enter,
-	.finish = acpi_suspend_finish,
-	.end = acpi_suspend_end,
+	.finish = acpi_pm_finish,
+	.end = acpi_pm_end,
+	.recover = acpi_pm_finish,
 };
 #endif /* CONFIG_SUSPEND */
 
@@ -240,22 +300,9 @@ __setup("acpi_s4_nosigcheck", acpi_s4_no
 static int acpi_hibernation_begin(void)
 {
 	acpi_target_sleep_state = ACPI_STATE_S4;
-
 	return 0;
 }
 
-static int acpi_hibernation_prepare(void)
-{
-	int error = acpi_sleep_prepare(ACPI_STATE_S4);
-
-	if (error) {
-		acpi_target_sleep_state = ACPI_STATE_S0;
-		return error;
-	}
-
-	return ACPI_SUCCESS(acpi_hw_disable_all_gpes()) ? 0 : -EFAULT;
-}
-
 static int acpi_hibernation_enter(void)
 {
 	acpi_status status = AE_OK;
@@ -291,52 +338,55 @@ static void acpi_hibernation_leave(void)
 	}
 }
 
-static void acpi_hibernation_finish(void)
+static void acpi_pm_enable_gpes(void)
 {
-	acpi_disable_wakeup_device(ACPI_STATE_S4);
-	acpi_leave_sleep_state(ACPI_STATE_S4);
-
-	/* reset firmware waking vector */
-	acpi_set_firmware_waking_vector((acpi_physical_address) 0);
-
-	acpi_target_sleep_state = ACPI_STATE_S0;
+	acpi_hw_enable_all_runtime_gpes();
 }
 
-static void acpi_hibernation_end(void)
-{
-	/*
-	 * This is necessary in case acpi_hibernation_finish() is not called
-	 * during a failing transition to the sleep state.
-	 */
-	acpi_target_sleep_state = ACPI_STATE_S0;
-}
+static struct platform_hibernation_ops acpi_hibernation_ops = {
+	.begin = acpi_hibernation_begin,
+	.end = acpi_pm_end,
+	.pre_snapshot = acpi_pm_prepare,
+	.finish = acpi_pm_finish,
+	.prepare = acpi_pm_prepare,
+	.enter = acpi_hibernation_enter,
+	.leave = acpi_hibernation_leave,
+	.pre_restore = acpi_pm_disable_gpes,
+	.restore_cleanup = acpi_pm_enable_gpes,
+};
 
-static int acpi_hibernation_pre_restore(void)
+/**
+ *	acpi_hibernation_begin_old - Set the target system sleep state to
+ *		ACPI_STATE_S4 and execute the _PTS control method.  This
+ *		function is used if the pre-ACPI 2.0 suspend ordering has been
+ *		requested.
+ */
+static int acpi_hibernation_begin_old(void)
 {
-	acpi_status status;
-
-	status = acpi_hw_disable_all_gpes();
-
-	return ACPI_SUCCESS(status) ? 0 : -EFAULT;
-}
+	int error = acpi_sleep_prepare(ACPI_STATE_S4);
 
-static void acpi_hibernation_restore_cleanup(void)
-{
-	acpi_hw_enable_all_runtime_gpes();
+	if (!error)
+		acpi_target_sleep_state = ACPI_STATE_S4;
+	return error;
 }
 
-static struct platform_hibernation_ops acpi_hibernation_ops = {
-	.begin = acpi_hibernation_begin,
-	.end = acpi_hibernation_end,
-	.pre_snapshot = acpi_hibernation_prepare,
-	.finish = acpi_hibernation_finish,
-	.prepare = acpi_hibernation_prepare,
+/*
+ * The following callbacks are used if the pre-ACPI 2.0 suspend ordering has
+ * been requested.
+ */
+static struct platform_hibernation_ops acpi_hibernation_ops_old = {
+	.begin = acpi_hibernation_begin_old,
+	.end = acpi_pm_end,
+	.pre_snapshot = acpi_pm_disable_gpes,
+	.finish = acpi_pm_finish,
+	.prepare = acpi_pm_disable_gpes,
 	.enter = acpi_hibernation_enter,
 	.leave = acpi_hibernation_leave,
-	.pre_restore = acpi_hibernation_pre_restore,
-	.restore_cleanup = acpi_hibernation_restore_cleanup,
+	.pre_restore = acpi_pm_disable_gpes,
+	.restore_cleanup = acpi_pm_enable_gpes,
+	.recover = acpi_pm_finish,
 };
-#endif				/* CONFIG_HIBERNATION */
+#endif /* CONFIG_HIBERNATION */
 
 int acpi_suspend(u32 acpi_state)
 {
@@ -478,13 +528,15 @@ int __init acpi_sleep_init(void)
 		}
 	}
 
-	suspend_set_ops(&acpi_suspend_ops);
+	suspend_set_ops(old_suspend_ordering ?
+		&acpi_suspend_ops_old : &acpi_suspend_ops);
 #endif
 
 #ifdef CONFIG_HIBERNATION
 	status = acpi_get_sleep_type_data(ACPI_STATE_S4, &type_a, &type_b);
 	if (ACPI_SUCCESS(status)) {
-		hibernation_set_ops(&acpi_hibernation_ops);
+		hibernation_set_ops(old_suspend_ordering ?
+			&acpi_hibernation_ops_old : &acpi_hibernation_ops);
 		sleep_states[ACPI_STATE_S4] = 1;
 		printk(" S4");
 		if (!nosigcheck) {
Index: linux-2.6/include/linux/suspend.h
===================================================================
--- linux-2.6.orig/include/linux/suspend.h
+++ linux-2.6/include/linux/suspend.h
@@ -86,6 +86,11 @@ typedef int __bitwise suspend_state_t;
  *	that implement @begin(), but platforms implementing @begin() should
  *	also provide a @end() which cleans up transitions aborted before
  *	@enter().
+ *
+ * @recover: Recover the platform from a suspend failure.
+ *	Called by the PM core if the suspending of devices fails.
+ *	This callback is optional and should only be implemented by platforms
+ *	which require special recovery actions in that situation.
  */
 struct platform_suspend_ops {
 	int (*valid)(suspend_state_t state);
@@ -94,6 +99,7 @@ struct platform_suspend_ops {
 	int (*enter)(suspend_state_t state);
 	void (*finish)(void);
 	void (*end)(void);
+	void (*recover)(void);
 };
 
 #ifdef CONFIG_SUSPEND
@@ -149,7 +155,7 @@ extern void mark_free_pages(struct zone 
  * The methods in this structure allow a platform to carry out special
  * operations required by it during a hibernation transition.
  *
- * All the methods below must be implemented.
+ * All the methods below, except for @recover(), must be implemented.
  *
  * @begin: Tell the platform driver that we're starting hibernation.
  *	Called right after shrinking memory and before freezing devices.
@@ -189,6 +195,11 @@ extern void mark_free_pages(struct zone 
  * @restore_cleanup: Clean up after a failing image restoration.
  *	Called right after the nonboot CPUs have been enabled and before
  *	thawing devices (runs with IRQs on).
+ *
+ * @recover: Recover the platform from a failure to suspend devices.
+ *	Called by the PM core if the suspending of devices during hibernation
+ *	fails.  This callback is optional and should only be implemented by
+ *	platforms which require special recovery actions in that situation.
  */
 struct platform_hibernation_ops {
 	int (*begin)(void);
@@ -200,6 +211,7 @@ struct platform_hibernation_ops {
 	void (*leave)(void);
 	int (*pre_restore)(void);
 	void (*restore_cleanup)(void);
+	void (*recover)(void);
 };
 
 #ifdef CONFIG_HIBERNATION
Index: linux-2.6/kernel/power/main.c
===================================================================
--- linux-2.6.orig/kernel/power/main.c
+++ linux-2.6/kernel/power/main.c
@@ -269,11 +269,11 @@ int suspend_devices_and_enter(suspend_st
 	error = device_suspend(PMSG_SUSPEND);
 	if (error) {
 		printk(KERN_ERR "PM: Some devices failed to suspend\n");
-		goto Resume_console;
+		goto Recover_platform;
 	}
 
 	if (suspend_test(TEST_DEVICES))
-		goto Resume_devices;
+		goto Recover_platform;
 
 	if (suspend_ops->prepare) {
 		error = suspend_ops->prepare();
@@ -300,6 +300,11 @@ int suspend_devices_and_enter(suspend_st
 	if (suspend_ops->end)
 		suspend_ops->end();
 	return error;
+
+ Recover_platform:
+	if (suspend_ops->recover)
+		suspend_ops->recover();
+	goto Resume_devices;
 }
 
 /**
Index: linux-2.6/kernel/power/disk.c
===================================================================
--- linux-2.6.orig/kernel/power/disk.c
+++ linux-2.6/kernel/power/disk.c
@@ -180,6 +180,17 @@ static void platform_restore_cleanup(int
 }
 
 /**
+ *	platform_recover - recover the platform from a failure to suspend
+ *	devices.
+ */
+
+static void platform_recover(int platform_mode)
+{
+	if (platform_mode && hibernation_ops && hibernation_ops->recover)
+		hibernation_ops->recover();
+}
+
+/**
  *	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.
@@ -258,10 +269,10 @@ int hibernation_snapshot(int platform_mo
 	suspend_console();
 	error = device_suspend(PMSG_FREEZE);
 	if (error)
-		goto Resume_console;
+		goto Recover_platform;
 
 	if (hibernation_test(TEST_DEVICES))
-		goto Resume_devices;
+		goto Recover_platform;
 
 	error = platform_pre_snapshot(platform_mode);
 	if (error || hibernation_test(TEST_PLATFORM))
@@ -285,11 +296,14 @@ int hibernation_snapshot(int platform_mo
  Resume_devices:
 	device_resume(in_suspend ?
 		(error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
- Resume_console:
 	resume_console();
  Close:
 	platform_end(platform_mode);
 	return error;
+
+ Recover_platform:
+	platform_recover(platform_mode);
+	goto Resume_devices;
 }
 
 /**
@@ -398,8 +412,11 @@ int hibernation_platform_enter(void)
 
 	suspend_console();
 	error = device_suspend(PMSG_HIBERNATE);
-	if (error)
-		goto Resume_console;
+	if (error) {
+		if (hibernation_ops->recover)
+			hibernation_ops->recover();
+		goto Resume_devices;
+	}
 
 	error = hibernation_ops->prepare();
 	if (error)
@@ -428,7 +445,6 @@ int hibernation_platform_enter(void)
 	hibernation_ops->finish();
  Resume_devices:
 	device_resume(PMSG_RESTORE);
- Resume_console:
 	resume_console();
  Close:
 	hibernation_ops->end();
Index: linux-2.6/drivers/base/power/main.c
===================================================================
--- linux-2.6.orig/drivers/base/power/main.c
+++ linux-2.6/drivers/base/power/main.c
@@ -781,8 +781,6 @@ int device_suspend(pm_message_t state)
 	error = dpm_prepare(state);
 	if (!error)
 		error = dpm_suspend(state);
-	if (error)
-		device_resume(resume_event(state));
 	return error;
 }
 EXPORT_SYMBOL_GPL(device_suspend);