Re: [PATCH v2] PM: add statistics debugfs file for suspend to ram

@@ -982,6 +1003,8 @@ int dpm_suspend(pm_message_t state)
 		error = async_error;
 	if (!error)
 		dpm_show_time(starttime, state, NULL);
+	else
+		suspend_stats.failed_suspend++;
 	return error;
 }

@@ -1090,6 +1113,8 @@ int dpm_suspend_start(pm_message_t state)
 	error = dpm_prepare(state);
 	if (!error)
 		error = dpm_suspend(state);
+	else
+		suspend_stats.failed_prepare++;
 	return error;
 }

 EXPORT_SYMBOL_GPL(dpm_suspend_start);

diff --git a/include/linux/suspend.h b/include/linux/suspend.h
index 6bbcef2..6a8ff23 100644
--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h

@@ -34,6 +34,22 @@ typedef int __bitwise suspend_state_t;
 #define PM_SUSPEND_MEM		((__force suspend_state_t) 3)
 #define PM_SUSPEND_MAX		((__force suspend_state_t) 4)
 
+struct suspend_stats {
+	int	success;
+	int	fail;
+	int	failed_freeze;
+	int	failed_prepare;
+	int	failed_suspend;
+	int	failed_suspend_noirq;
+	int	failed_resume;
+	int	failed_resume_noirq;
+#define	REC_FAILED_DEV_NUM	2
+	char	failed_devs[REC_FAILED_DEV_NUM][40];
+	int	last_failed;
+};
+
+extern struct suspend_stats suspend_stats;
+
 /**
  * struct platform_suspend_ops - Callbacks for managing platform dependent
  *	system sleep states.

diff --git a/kernel/power/main.c b/kernel/power/main.c
index 6c601f8..0977f5d 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c

@@ -12,6 +12,8 @@
 #include <linux/string.h>
 #include <linux/resume-trace.h>
 #include <linux/workqueue.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
 
 #include "power.h"
 

@@ -133,6 +135,59 @@ power_attr(pm_test);
 
 #endif /* CONFIG_PM_SLEEP */
 
+#ifdef CONFIG_DEBUG_FS
+static int suspend_stats_show(struct seq_file *s, void *unused)
+{
+	int i, index, last_index;
+
+	last_index = suspend_stats.last_failed + REC_FAILED_DEV_NUM - 1;
+	last_index %= REC_FAILED_DEV_NUM;
+	seq_printf(s, "%s: %d\n%s: %d\n%s: %d\n%s: %d\n"
+			"%s: %d\n%s: %d\n%s: %d\n%s: %d\n",
+			"success", suspend_stats.success,
+			"fail", suspend_stats.fail,
+			"failed_freeze", suspend_stats.failed_freeze,
+			"failed_prepare", suspend_stats.failed_prepare,
+			"failed_suspend", suspend_stats.failed_suspend,
+			"failed_suspend_noirq",
+				suspend_stats.failed_suspend_noirq,
+			"failed_resume", suspend_stats.failed_resume,
+			"failed_resume_noirq",
+				suspend_stats.failed_resume_noirq);
+	seq_printf(s,	"failed_devs:\n  last_failed:\t%s\n",
+			suspend_stats.failed_devs[last_index]);
+	for (i = 1; i < REC_FAILED_DEV_NUM; i++) {
+		index = last_index + REC_FAILED_DEV_NUM - i;
+		index %= REC_FAILED_DEV_NUM;
+		seq_printf(s, "\t\t%s\n",
+			suspend_stats.failed_devs[index]);
+	}
+
+	return 0;
+}
+
+static int suspend_stats_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, suspend_stats_show, NULL);
+}
+
+static const struct file_operations suspend_stats_operations = {
+	.open           = suspend_stats_open,
+	.read           = seq_read,
+	.llseek         = seq_lseek,
+	.release        = single_release,
+};
+
+static int __init pm_debugfs_init(void)
+{
+	debugfs_create_file("suspend_stats", S_IFREG | S_IRUGO,
+			NULL, NULL, &suspend_stats_operations);
+	return 0;
+}
+
+late_initcall(pm_debugfs_init);
+#endif /* CONFIG_DEBUG_FS */
+
 struct kobject *power_kobj;
 
 /**

@@ -194,6 +249,10 @@ static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
 	}
 	if (state < PM_SUSPEND_MAX && *s)
 		error = enter_state(state);
+		if (error)
+			suspend_stats.fail++;
+		else
+			suspend_stats.success++;
 #endif
 
  Exit:

diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index b6b71ad..9bb4281 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c

@@ -106,6 +106,8 @@ static int suspend_prepare(void)
 	error = suspend_freeze_processes();
 	if (!error)
 		return 0;
+	else
+		suspend_stats.failed_freeze++;