PM / Suspend: Add statistics debugfs file for suspend to RAM

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.

Signed-off-by: ShuoX Liu <shuox.liu@intel.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

diff --git a/Documentation/power/basic-pm-debugging.txt b/Documentation/power/basic-pm-debugging.txt
index ddd78172ef738d2c3f52dcea70f61cb0591670c2..62eca080a71b2313196b4588dfa817dae5ed573a 100644 (file)
--- 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 a85459126bc6a5ef9cdb737140353084d0bd8c3e..23b755df767132fd15173fcb4b4bd74072a7e84c 100644 (file)
--- 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 6bbcef22e1054766f01a36f6e352c0ea5d06770c..76f42e49b72deea43a190677822070bea4e53eb1 100644 (file)
--- 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 6c601f871964408e7df2b376dd69d86006103b0e..2757acba8e8a08459517c6d77b895df84044bf80 100644 (file)
--- 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 b6b71ad2208fd1a0a04bd31fe4437f6d99bf7f9d..595a3dd56a8a832c9029086de9b2a11460951d3d 100644 (file)
--- 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);