Power management debug option to configure device suspend/resume watchdogs.
Available options are:
1. Enable/disable the feature.
2. Select triggered watchdog action between:
- system panic (default)
- dump stacktrace
- log event
3. Select timeout value for the watchdog(s).
Minor changes were made to watchdog code to accommodate this feature.
Cc: Android Kernel Team <kernel-t...@android.com>
Cc: Colin Cross <ccr...@android.com>
Cc: Todd Poynor <toddpoy...@google.com>
Cc: San Mehat <s...@google.com>
Cc: Benoit Goby <ben...@android.com>
Cc: John Stultz <john.stu...@linaro.org>
Cc: Pavel Machek <pa...@ucw.cz>
Cc: Rafael J. Wysocki <r...@sisk.pl>
Cc: Len Brown <len.br...@intel.com>
Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Signed-off-by: Zoran Markovic <zoran.marko...@linaro.org>
---
drivers/base/power/main.c | 37 ++++++++++++++++++++++++++--------
kernel/power/Kconfig | 48 +++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 77 insertions(+), 8 deletions(-)
diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index a6a02c0..8e0bb33 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -392,6 +392,26 @@ static int dpm_run_callback(pm_callback_t cb, struct
device *dev,
return error;
}
+#ifdef CONFIG_DPM_WD
+/**
+ * dpm_wd_action - recovery from suspend/resume watchdog timeout
+ * @wd: Watchdog. Must be allocated on the stack.
+ */
+#if defined(CONFIG_DPM_WD_ACTION_STACKTRACE)
+static inline void dpm_wd_action(struct dpm_watchdog *wd)
+{
+ show_stack(wd->tsk, NULL);
+}
+#elif defined(CONFIG_DPM_WD_ACTION_PANIC)
+static inline void dpm_wd_action(struct dpm_watchdog *wd)
+{
+ panic("%s: unrecoverable failure\n", dev_name(wd->dev));
+}
+#else /* CONFIG_DPM_WD_ACTION_LOG */
+/* event already logged in dpm_wd_handler() */
+#define dpm_wd_action(x)
+#endif
+
/**
* dpm_wd_handler - Driver suspend / resume watchdog handler.
*
@@ -402,13 +422,9 @@ static int dpm_run_callback(pm_callback_t cb, struct
device *dev,
static void dpm_wd_handler(unsigned long data)
{
struct dpm_watchdog *wd = (void *)data;
- struct device *dev = wd->dev;
- struct task_struct *tsk = wd->tsk;
-
- dev_emerg(dev, "**** DPM device timeout ****\n");
- show_stack(tsk, NULL);
- BUG();
+ dev_emerg(wd->dev, "**** DPM device timeout ****\n");
+ dpm_wd_action(wd);
}
/**
@@ -424,14 +440,15 @@ static void dpm_wd_set(struct dpm_watchdog *wd, struct
device *dev)
wd->tsk = get_current();
init_timer_on_stack(timer);
- timer->expires = jiffies + HZ * 12;
+ /* use same timeout value for both suspend and resume */
+ timer->expires = jiffies + HZ * CONFIG_DPM_WD_TIMEOUT;
timer->function = dpm_wd_handler;
timer->data = (unsigned long)wd;
add_timer(timer);
}
/**
- * dpm_wd_clear - Disable pm watchdog.
+ * dpm_wd_clear - Disable suspend/resume watchdog.
* @wd: Watchdog to disable.
*/
static void dpm_wd_clear(struct dpm_watchdog *wd)
@@ -441,6 +458,10 @@ static void dpm_wd_clear(struct dpm_watchdog *wd)
del_timer_sync(timer);
destroy_timer_on_stack(timer);
}
+#else
+#define dpm_wd_set(x, y)
+#define dpm_wd_clear(x)
+#endif
/*------------------------- Resume routines -------------------------*/
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index edc8bdd..339caa1 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -179,6 +179,54 @@ config PM_SLEEP_DEBUG
def_bool y
depends on PM_DEBUG && PM_SLEEP
+config DPM_WD
+ bool "Device suspend/resume watchdog"
+ depends on PM_DEBUG
+ ---help---
+ Sets up a watchdog timer to capture drivers that are
+ locked up attempting to suspend/resume a device.
+ A detected lockup causes a configurable watchdog action,
+ such as logging the event, dumping the stack trace or
+ kernel panic.
+
+choice
+ prompt "Watchdog recovery action"
+ default DPM_WD_ACTION_PANIC
+ depends on DPM_WD
+ ---help---
+ Select recovery action triggered by suspend/resume watchdog.
+
+config DPM_WD_ACTION_PANIC
+ bool "System panic"
+ ---help---
+ When selected, a lockup during device's suspend or
+ resume would cause a system panic. This would immediately
+ capture user's attention. Panic message can be observed in
+ subsequent boot session using pstore.
+
+config DPM_WD_ACTION_STACKTRACE
+ bool "Dump stack"
+ ---help---
+ When selected, a lockup during device's suspend or
+ resume would cause the caller's stack to be
+ captured in the system log. The stack trace shows
+ which driver call caused a lockup.
+
+config DPM_WD_ACTION_LOG
+ bool "Log event"
+ ---help---
+ When selected, a lockup during device's suspend or
+ resume would cause the watchdog timeout event to be
+ logged in the system log.
+
+endchoice
+
+config DPM_WD_TIMEOUT
+ int "Watchdog timeout in seconds"
+ range 1 120
+ default 12
+ depends on DPM_WD
+
config PM_TRACE
bool
help
--
1.7.9.5
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