[Please consider as 2.6.22 material.]
---
From: Rafael J. Wysocki <[email protected]>
Commit 52ade9b3b97fd3bea42842a056fe0786c28d0555 changed the suspend code
ordering to execute pm_ops->prepare() after the device model per-device
.suspend() calls in order to fix some ACPI-related issues. Unfortunately, it
broke the at91 platform which assumed that pm_ops->prepare() would be called
before suspending devices.
at91 used pm_ops->prepare() to get notified of the target system sleep state, so
that it could use this information while suspending devices. However, with the
current suspend code ordering pm_ops->prepare() is called too late for this
purpose. Thus, at91 needs an additional method in 'struct pm_ops' that will
be used for notifying the platform of the target system sleep state. Moreover,
in the future such a method will also be needed by ACPI.
This patch adds the .set_target() method to 'struct pm_ops' and makes the
suspend code call it, if implemented, before executing the device model
per-device .suspend() calls. It also modifies the at91 code to implement
pm_ops->set_target() instead of pm_ops->prepare().
Signed-off-by: Rafael J. Wysocki <[email protected]>
Acked-by: David Brownell <[email protected]>
---
arch/arm/mach-at91/pm.c | 4 +-
include/linux/pm.h | 66 +++++++++++++++++++++++++++++++++++-------------
kernel/power/main.c | 6 +++-
3 files changed, 56 insertions(+), 20 deletions(-)
Index: linux-2.6.22-rc6/include/linux/pm.h
===================================================================
--- linux-2.6.22-rc6.orig/include/linux/pm.h 2007-06-25 21:09:18.000000000 +0200
+++ linux-2.6.22-rc6/include/linux/pm.h 2007-06-25 21:09:30.000000000 +0200
@@ -110,37 +110,67 @@ typedef int __bitwise suspend_state_t;
#define PM_SUSPEND_MAX ((__force suspend_state_t) 4)
/**
- * struct pm_ops - Callbacks for managing platform dependent suspend states.
- * @valid: Callback to determine whether the given state can be entered.
- * Valid states are advertised in /sys/power/state but can still
- * be rejected by prepare or enter if the conditions aren't right.
- * There is a %pm_valid_only_mem function available that can be assigned
- * to this if you only implement mem sleep.
+ * struct pm_ops - Callbacks for managing platform dependent system sleep
+ * states.
*
- * @prepare: Prepare the platform for the given suspend state. Can return a
- * negative error code if necessary.
- *
- * @enter: Enter the given suspend state, must be assigned. Can return a
- * negative error code if necessary.
- *
- * @finish: Called when the system has left the given state and all devices
- * are resumed. The return value is ignored.
+ * @valid: Callback to determine if given system sleep state is supported by
+ * the platform.
+ * Valid (ie. supported) states are advertised in /sys/power/state. Note
+ * that it still may be impossible to enter given system sleep state if the
+ * conditions aren't right.
+ * There is the %pm_valid_only_mem function available that can be assigned
+ * to this if the platform only supports mem sleep.
+ *
+ * @set_target: Tell the platform which system sleep state is going to be
+ * entered.
+ * @set_target() is executed right prior to suspending devices. The
+ * information conveyed to the platform code by @set_target() should be
+ * disregarded by the platform as soon as @finish() is executed and if
+ * @prepare() fails. If @set_target() fails (ie. returns nonzero),
+ * @prepare(), @enter() and @finish() will not be called by the PM core.
+ * This callback is optional. However, if it is implemented, the argument
+ * passed to @prepare(), @enter() and @finish() is meaningless and should
+ * be ignored.
+ *
+ * @prepare: Prepare the platform for entering the system sleep state indicated
+ * by @set_target() or represented by the argument if @set_target() is not
+ * implemented.
+ * @prepare() is called right after devices have been suspended (ie. the
+ * appropriate .suspend() method has been executed for each device) and
+ * before the nonboot CPUs are disabled (it is executed with IRQs enabled).
+ * This callback is optional. It returns 0 on success or a negative
+ * error code otherwise, in which case the system cannot enter the desired
+ * sleep state (@enter() and @finish() will not be called in that case).
+ *
+ * @enter: Enter the system sleep state indicated by @set_target() or
+ * represented by the argument if @set_target() is not implemented.
+ * This callback is mandatory. It returns 0 on success or a negative
+ * error code otherwise, in which case the system cannot enter the desired
+ * sleep state.
+ *
+ * @finish: Called when the system has just left a sleep state, right after
+ * the nonboot CPUs have been enabled and before devices are resumed (it is
+ * executed with IRQs enabled). If @set_target() is not implemented, the
+ * argument represents the sleep state being left.
+ * This callback is optional, but should be implemented by the platforms
+ * that implement @prepare(). If implemented, it is always called after
+ * @enter() (even if @enter() fails).
*/
struct pm_ops {
int (*valid)(suspend_state_t state);
+ int (*set_target)(suspend_state_t state);
int (*prepare)(suspend_state_t state);
int (*enter)(suspend_state_t state);
int (*finish)(suspend_state_t state);
};
+extern struct pm_ops *pm_ops;
+
/**
* pm_set_ops - set platform dependent power management ops
* @pm_ops: The new power management operations to set.
*/
extern void pm_set_ops(struct pm_ops *pm_ops);
-extern struct pm_ops *pm_ops;
-extern int pm_suspend(suspend_state_t state);
-
extern int pm_valid_only_mem(suspend_state_t state);
/**
@@ -161,6 +191,8 @@ extern void arch_suspend_disable_irqs(vo
*/
extern void arch_suspend_enable_irqs(void);
+extern int pm_suspend(suspend_state_t state);
+
/*
* Device power management
*/
Index: linux-2.6.22-rc6/kernel/power/main.c
===================================================================
--- linux-2.6.22-rc6.orig/kernel/power/main.c 2007-06-25 21:09:18.000000000 +0200
+++ linux-2.6.22-rc6/kernel/power/main.c 2007-06-25 21:09:30.000000000 +0200
@@ -15,7 +15,6 @@
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/init.h>
-#include <linux/pm.h>
#include <linux/console.h>
#include <linux/cpu.h>
#include <linux/resume-trace.h>
@@ -161,6 +160,11 @@ int suspend_devices_and_enter(suspend_st
if (!pm_ops)
return -ENOSYS;
+ if (pm_ops->set_target) {
+ error = pm_ops->set_target(state);
+ if (error)
+ return error;
+ }
suspend_console();
error = device_suspend(PMSG_SUSPEND);
if (error) {
Index: linux-2.6.22-rc6/arch/arm/mach-at91/pm.c
===================================================================
--- linux-2.6.22-rc6.orig/arch/arm/mach-at91/pm.c 2007-06-25 21:09:18.000000000 +0200
+++ linux-2.6.22-rc6/arch/arm/mach-at91/pm.c 2007-06-25 21:09:30.000000000 +0200
@@ -53,7 +53,7 @@ static suspend_state_t target_state;
/*
* Called after processes are frozen, but before we shutdown devices.
*/
-static int at91_pm_prepare(suspend_state_t state)
+static int at91_pm_set_target(suspend_state_t state)
{
target_state = state;
return 0;
@@ -201,7 +201,7 @@ error:
static struct pm_ops at91_pm_ops ={
.valid = at91_pm_valid_state,
- .prepare = at91_pm_prepare,
+ .set_target = at91_pm_set_target,
.enter = at91_pm_enter,
};
-
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