[PATCH v4] PM: add statistics debugfs file for suspend to ram

Liu, ShuoX
2011-08-10T07:29:32Z

From: ShuoX Liu <shuox.liu@intel.com>

Record S3 failure time about each reason and the latest two failed
devices' names in S3 progress.
We can check it through 'suspend_stats' entry in debugfs.

The motivation of the patch:

We are enabling power features on Medfield. Comparing with PC/notebook,
a mobile enters/exits suspend-2-ram (we call it s3 on Medfield) far
more frequently. If it can't enter suspend-2-ram in time, the power
might be used up soon.

We often find sometimes, a device suspend fails. Then, system retries
s3 over and over again. As display is off, testers and developers
don't know what happens.

Some testers and developers complain they don't know if system
tries suspend-2-ram, and what device fails to suspend. They need
such info for a quick check. The patch adds suspend_stats under
debugfs for users to check suspend to RAM statistics quickly.

If not using this patch, we have other methods to get info about
what device fails. One is to turn on CONFIG_PM_DEBUG, but users
would get too much info and testers need recompile the system.

In addition, dynamic debug is another good tool to dump debug info.
But it still doesn't match our utilization scenario closely.
1) user need write a user space parser to process the syslog output;
2) Our testing scenario is we leave the mobile for at least hours.
Then, check its status. No serial console available during the
testing. One is because console would be suspended, and the other
is serial console connecting with spi or HSU devices would consume
power. These devices are powered off at suspend-2-ram.

Thank Greg, MyungJoo and Rafael for their great comments.

Change Log:
V4: Improve output format.
V3: Change some programming styles.
V2:
1) Change the sysfs entry to debugfs.
2) Add some explanation in document file.

Contribution:
yanmin_zhang@linux.intel.com

Signed-off-by: ShuoX Liu <shuox.liu@intel.com>
---
Documentation/power/basic-pm-debugging.txt | 24 +++++++
drivers/base/power/main.c | 31 +++++++--
include/linux/suspend.h | 52 ++++++++++++++
kernel/power/main.c | 102 ++++++++++++++++++++++++++++
kernel/power/suspend.c | 17 ++++-
5 files changed, 218 insertions(+), 8 deletions(-)

diff --git a/Documentation/power/basic-pm-debugging.txt b/Documentation/power/basic-pm-debugging.txt
index ddd7817..62eca08 100644
--- a/Documentation/power/basic-pm-debugging.txt
+++ b/Documentation/power/basic-pm-debugging.txt
@@ -201,3 +201,27 @@ case, you may be able to search for failing drivers by following the procedure
analogous to the one described in section 1. If you find some failing drivers,
you will have to unload them every time before an STR transition (ie. before
you run s2ram), and please report the problems with them.
+
+There is a debugfs entry which shows the suspend to RAM statistics. Here is an
+example of its output.
+ # mount -t debugfs none /sys/kernel/debug
+ # cat /sys/kernel/debug/suspend_stats
+ success: 20
+ fail: 5
+ failed_freeze: 0
+ failed_prepare: 0
+ failed_suspend: 5
+ failed_suspend_noirq: 0
+ failed_resume: 0
+ failed_resume_noirq: 0
+ failures:
+ last_failed_dev: alarm
+ adc
+ last_failed_errno: -16
+ -16
+ last_failed_step: suspend
+ suspend
+Field success means the success number of suspend to RAM, and field fail means
+the failure number. Others are the failure number of different steps of suspend
+to RAM. suspend_stats just lists the last 2 failed devices, error number and
+failed step of suspend.
diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index a854591..23b755d 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -46,6 +46,7 @@ LIST_HEAD(dpm_prepared_list);
LIST_HEAD(dpm_suspended_list);
LIST_HEAD(dpm_noirq_list);

+struct suspend_stats suspend_stats;
static DEFINE_MUTEX(dpm_list_mtx);
static pm_message_t pm_transition;

@@ -464,8 +465,12 @@ void dpm_resume_noirq(pm_message_t state)
mutex_unlock(&dpm_list_mtx);

error = device_resume_noirq(dev, state);
- if (error)
+ if (error) {
+ suspend_stats.failed_resume_noirq++;
+ dpm_save_failed_step(SUSPEND_RESUME_NOIRQ);
+ dpm_save_failed_dev(dev_name(dev));
pm_dev_err(dev, state, " early", error);
+ }

mutex_lock(&dpm_list_mtx);
put_device(dev);
@@ -626,8 +631,12 @@ void dpm_resume(pm_message_t state)
mutex_unlock(&dpm_list_mtx);

error = device_resume(dev, state, false);
- if (error)
+ if (error) {
+ suspend_stats.failed_resume++;
+ dpm_save_failed_step(SUSPEND_RESUME);
+ dpm_save_failed_dev(dev_name(dev));
pm_dev_err(dev, state, "", error);
+ }

mutex_lock(&dpm_list_mtx);
}
@@ -802,6 +811,9 @@ int dpm_suspend_noirq(pm_message_t state)
mutex_lock(&dpm_list_mtx);
if (error) {
pm_dev_err(dev, state, " late", error);
+ suspend_stats.failed_suspend_noirq++;
+ dpm_save_failed_step(SUSPEND_SUSPEND_NOIRQ);
+ dpm_save_failed_dev(dev_name(dev));
put_device(dev);
break;
}
@@ -923,8 +935,10 @@ static void async_suspend(void *data, async_cookie_t cookie)
int error;

error = __device_suspend(dev, pm_transition, true);
- if (error)
+ if (error) {
+ dpm_save_failed_dev(dev_name(dev));
pm_dev_err(dev, pm_transition, " async", error);
+ }

put_device(dev);
}
@@ -967,6 +981,7 @@ int dpm_suspend(pm_message_t state)
mutex_lock(&dpm_list_mtx);
if (error) {
pm_dev_err(dev, state, "", error);
+ dpm_save_failed_dev(dev_name(dev));
put_device(dev);
break;
}
@@ -980,7 +995,10 @@ int dpm_suspend(pm_message_t state)
async_synchronize_full();
if (!error)
error = async_error;
- if (!error)
+ if (error) {
+ suspend_stats.failed_suspend++;
+ dpm_save_failed_step(SUSPEND_SUSPEND);
+ } else
dpm_show_time(starttime, state, NULL);
return error;
}
@@ -1088,7 +1106,10 @@ int dpm_suspend_start(pm_message_t state)
int error;

error = dpm_prepare(state);
- if (!error)
+ if (error) {
+ suspend_stats.failed_prepare++;
+ dpm_save_failed_step(SUSPEND_PREPARE);
+ } else
error = dpm_suspend(state);
return error;
}
diff --git a/include/linux/suspend.h b/include/linux/suspend.h
index 6bbcef2..76f42e4 100644
--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h
@@ -34,6 +34,58 @@ typedef int __bitwise suspend_state_t;
#define PM_SUSPEND_MEM ((__force suspend_state_t) 3)
#define PM_SUSPEND_MAX ((__force suspend_state_t) 4)

+enum suspend_stat_step {
+ SUSPEND_FREEZE = 1,
+ SUSPEND_PREPARE,
+ SUSPEND_SUSPEND,
+ SUSPEND_SUSPEND_NOIRQ,
+ SUSPEND_RESUME_NOIRQ,
+ SUSPEND_RESUME
+};
+
+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_NUM 2
+ int last_failed_dev;
+ char failed_devs[REC_FAILED_NUM][40];
+ int last_failed_errno;
+ int errno[REC_FAILED_NUM];
+ int last_failed_step;
+ enum suspend_stat_step failed_steps[REC_FAILED_NUM];
+};
+
+extern struct suspend_stats suspend_stats;
+
+static inline void dpm_save_failed_dev(const char *name)
+{
+ strlcpy(suspend_stats.failed_devs[suspend_stats.last_failed_dev],
+ name,
+ sizeof(suspend_stats.failed_devs[0]));
+ suspend_stats.last_failed_dev++;
+ suspend_stats.last_failed_dev %= REC_FAILED_NUM;
+}
+
+static inline void dpm_save_failed_errno(int err)
+{
+ suspend_stats.errno[suspend_stats.last_failed_errno] = err;
+ suspend_stats.last_failed_errno++;
+ suspend_stats.last_failed_errno %= REC_FAILED_NUM;
+}
+
+static inline void dpm_save_failed_step(enum suspend_stat_step step)
+{
+ suspend_stats.failed_steps[suspend_stats.last_failed_step] = step;
+ suspend_stats.last_failed_step++;
+ suspend_stats.last_failed_step %= REC_FAILED_NUM;
+}
+
/**
* 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..2757acb 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 +135,101 @@ power_attr(pm_test);

#endif /* CONFIG_PM_SLEEP */

+#ifdef CONFIG_DEBUG_FS
+static char *suspend_step_name(enum suspend_stat_step step)
+{
+ switch (step) {
+ case SUSPEND_FREEZE:
+ return "freeze";
+ case SUSPEND_PREPARE:
+ return "prepare";
+ case SUSPEND_SUSPEND:
+ return "suspend";
+ case SUSPEND_SUSPEND_NOIRQ:
+ return "suspend_noirq";
+ case SUSPEND_RESUME_NOIRQ:
+ return "resume_noirq";
+ case SUSPEND_RESUME:
+ return "resume";
+ default:
+ return "";
+ }
+}
+
+static int suspend_stats_show(struct seq_file *s, void *unused)
+{
+ int i, index, last_dev, last_errno, last_step;
+
+ last_dev = suspend_stats.last_failed_dev + REC_FAILED_NUM - 1;
+ last_dev %= REC_FAILED_NUM;
+ last_errno = suspend_stats.last_failed_errno + REC_FAILED_NUM - 1;
+ last_errno %= REC_FAILED_NUM;
+ last_step = suspend_stats.last_failed_step + REC_FAILED_NUM - 1;
+ last_step %= REC_FAILED_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, "failures:\n last_failed_dev:\t%-s\n",
+ suspend_stats.failed_devs[last_dev]);
+ for (i = 1; i < REC_FAILED_NUM; i++) {
+ index = last_dev + REC_FAILED_NUM - i;
+ index %= REC_FAILED_NUM;
+ seq_printf(s, "\t\t\t%-s\n",
+ suspend_stats.failed_devs[index]);
+ }
+ seq_printf(s, " last_failed_errno:\t%-d\n",
+ suspend_stats.errno[last_errno]);
+ for (i = 1; i < REC_FAILED_NUM; i++) {
+ index = last_errno + REC_FAILED_NUM - i;
+ index %= REC_FAILED_NUM;
+ seq_printf(s, "\t\t\t%-d\n",
+ suspend_stats.errno[index]);
+ }
+ seq_printf(s, " last_failed_step:\t%-s\n",
+ suspend_step_name(
+ suspend_stats.failed_steps[last_step]));
+ for (i = 1; i < REC_FAILED_NUM; i++) {
+ index = last_step + REC_FAILED_NUM - i;
+ index %= REC_FAILED_NUM;
+ seq_printf(s, "\t\t\t%-s\n",
+ suspend_step_name(
+ suspend_stats.failed_steps[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 +291,11 @@ 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++;
+ dpm_save_failed_errno(error);
+ } else
+ suspend_stats.success++;
#endif

Exit:
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index b6b71ad..595a3dd 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -104,7 +104,10 @@ static int suspend_prepare(void)
goto Finish;

error = suspend_freeze_processes();
- if (!error)
+ if (error) {
+ suspend_stats.failed_freeze++;
+ dpm_save_failed_step(SUSPEND_FREEZE);
+ } else
return 0;

suspend_thaw_processes();
@@ -315,8 +318,16 @@ int enter_state(suspend_state_t state)
*/
int pm_suspend(suspend_state_t state)
{
- if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
- return enter_state(state);
+ int ret;
+ if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX) {
+ ret = enter_state(state);
+ if (ret) {
+ suspend_stats.fail++;
+ dpm_save_failed_errno(ret);
+ } else
+ suspend_stats.success++;
+ return ret;
+ }
return -EINVAL;
}
EXPORT_SYMBOL(pm_suspend);
--
1.7.1