[PATCH 4/8] Suspend: Testing facility (rev. 2)

Rafael J. Wysocki
2007-11-19T22:40:31Z

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

Introduce sysfs attribute /sys/power/pm_test allowing one to test the suspend
core code.  Namely, writing one of the strings:

freezer
devices
platform
processors
core

to this file causes the suspend code to work in one of the test modes defined as
follows:

freezer
- test the freezing of processes

devices
- test the freezing of processes and suspending of devices

platform
- test the freezing of processes, suspending of devices and platform global
control methods(*)

processors
- test the freezing of processes, suspending of devices, platform global
control methods and the disabling of nonboot CPUs

core
- test the freezing of processes, suspending of devices, platform global
control methods, the disabling of nonboot CPUs and suspending of
platform/system devices

(*) These are ACPI global control methods on ACPI systems

Then, if a suspend is started by normal means, the suspend core will perform
its normal operations up to the point indicated by given test level.  Next, it
will wait for 5 seconds and carry out the resume operations needed to transition
the system back to the fully functional state.

Writing "none" to /sys/power/pm_test turns the testing off.

When open for reading, /sys/power/pm_test contains a space-separated list of all
available tests (including "none" that represents the normal functionality) in
which the current test level is indicated by square brackets.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
---
kernel/power/main.c | 109 ++++++++++++++++++++++++++++++++++++++++++++++-----
kernel/power/power.h | 18 ++++++++
2 files changed, 118 insertions(+), 9 deletions(-)

Index: linux-2.6/kernel/power/main.c
===================================================================
--- linux-2.6.orig/kernel/power/main.c
+++ linux-2.6/kernel/power/main.c
@@ -28,6 +28,80 @@ BLOCKING_NOTIFIER_HEAD(pm_chain_head);

DEFINE_MUTEX(pm_mutex);

+#ifdef CONFIG_PM_DEBUG
+int pm_test_level = TEST_NONE;
+
+static int suspend_test(int level)
+{
+ if (pm_test_level == level) {
+ printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
+ mdelay(5000);
+ return 1;
+ }
+ return 0;
+}
+
+static const char * const pm_tests[__TEST_AFTER_LAST] = {
+ [TEST_NONE] = "none",
+ [TEST_CORE] = "core",
+ [TEST_CPUS] = "processors",
+ [TEST_PLATFORM] = "platform",
+ [TEST_DEVICES] = "devices",
+ [TEST_FREEZER] = "freezer",
+};
+
+static ssize_t pm_test_show(struct kset *kset, char *buf)
+{
+ char *s = buf;
+ int level;
+
+ for (level = TEST_FIRST; level <= TEST_MAX; level++)
+ if (pm_tests[level]) {
+ if (level == pm_test_level)
+ s += sprintf(s, "[%s] ", pm_tests[level]);
+ else
+ s += sprintf(s, "%s ", pm_tests[level]);
+ }
+
+ if (s != buf)
+ /* convert the last space to a newline */
+ *(s-1) = '\n';
+
+ return (s - buf);
+}
+
+static ssize_t pm_test_store(struct kset *kset, const char *buf, size_t n)
+{
+ const char * const *s;
+ int level;
+ char *p;
+ int len;
+ int error = -EINVAL;
+
+ p = memchr(buf, '\n', n);
+ len = p ? p - buf : n;
+
+ mutex_lock(&pm_mutex);
+
+ level = TEST_FIRST;
+ for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)
+ if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) {
+ pm_test_level = level;
+ error = 0;
+ break;
+ }
+
+ mutex_unlock(&pm_mutex);
+
+ return error ? error : n;
+}
+
+power_attr(pm_test);
+#else /* !CONFIG_PM_DEBUG */
+static inline int suspend_test(int level) { return 0; }
+#endif /* !CONFIG_PM_DEBUG */
+
+
#ifdef CONFIG_SUSPEND

/* This is just an arbitrary number */
@@ -133,7 +207,10 @@ static int suspend_enter(suspend_state_t
printk(KERN_ERR "Some devices failed to power down\n");
goto Done;
}
- error = suspend_ops->enter(state);
+
+ if (!suspend_test(TEST_CORE))
+ error = suspend_ops->enter(state);
+
device_power_up();
Done:
arch_suspend_enable_irqs();
@@ -164,16 +241,25 @@ int suspend_devices_and_enter(suspend_st
printk(KERN_ERR "Some devices failed to suspend\n");
goto Resume_console;
}
+
+ if (suspend_test(TEST_DEVICES))
+ goto Resume_devices;
+
if (suspend_ops->prepare) {
error = suspend_ops->prepare();
if (error)
goto Resume_devices;
}
+
+ if (suspend_test(TEST_PLATFORM))
+ goto Finish;
+
error = disable_nonboot_cpus();
- if (!error)
+ if (!error && !suspend_test(TEST_CPUS))
suspend_enter(state);

enable_nonboot_cpus();
+ Finish:
if (suspend_ops->finish)
suspend_ops->finish();
Resume_devices:
@@ -240,12 +326,17 @@ static int enter_state(suspend_state_t s
printk("done.\n");

pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
- if ((error = suspend_prepare()))
+ error = suspend_prepare();
+ if (error)
goto Unlock;

+ if (suspend_test(TEST_FREEZER))
+ goto Finish;
+
pr_debug("PM: Entering %s sleep\n", pm_states[state]);
error = suspend_devices_and_enter(state);

+ Finish:
pr_debug("PM: Finishing wakeup.\n");
suspend_finish();
Unlock:
@@ -363,18 +454,18 @@ pm_trace_store(struct kset *kset, const
}

power_attr(pm_trace);
+#endif /* CONFIG_PM_TRACE */

static struct attribute * g[] = {
&state_attr.attr,
+#ifdef CONFIG_PM_TRACE
&pm_trace_attr.attr,
+#endif
+#ifdef CONFIG_PM_DEBUG
+ &pm_test_attr.attr,
+#endif
NULL,
};
-#else
-static struct attribute * g[] = {
- &state_attr.attr,
- NULL,
-};
-#endif /* CONFIG_PM_TRACE */

static struct attribute_group attr_group = {
.attrs = g,
Index: linux-2.6/kernel/power/power.h
===================================================================
--- linux-2.6.orig/kernel/power/power.h
+++ linux-2.6/kernel/power/power.h
@@ -190,3 +190,21 @@ int restore_highmem(void);
static inline unsigned int count_highmem_pages(void) { return 0; }
static inline int restore_highmem(void) { return 0; }
#endif
+
+/*
+ * Suspend test levels
+ */
+enum {
+ /* keep first */
+ TEST_NONE,
+ TEST_CORE,
+ TEST_CPUS,
+ TEST_PLATFORM,
+ TEST_DEVICES,
+ TEST_FREEZER,
+ /* keep last */
+ __TEST_AFTER_LAST
+};
+
+#define TEST_FIRST TEST_NONE
+#define TEST_MAX (__TEST_AFTER_LAST - 1)

-
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