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drivers: power: Add watchdog timer to catch drivers which lockup during suspend.

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Rather than hard-lock the kernel, we now BUG() when a driver takes
> 3 seconds to suspend. If the underlying platform supports panic dumps,
then the data can be collected for debug.

Signed-off-by: San Mehat <san@google.com>
This commit is contained in:
San Mehat
2009-08-13 09:40:42 -07:00
committed by Colin Cross
parent 3b02c046c3
commit 4b66188a33
1 changed files with 45 additions and 0 deletions
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45
drivers/base/power/main.c
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@@ -26,6 +26,7 @@
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/async.h>
#include <linux/timer.h>
#include "../base.h"
#include "power.h"
@@ -45,6 +46,9 @@ LIST_HEAD(dpm_list);
static DEFINE_MUTEX(dpm_list_mtx);
static pm_message_t pm_transition;
static void dpm_drv_timeout(unsigned long data);
static DEFINE_TIMER(dpm_drv_wd, dpm_drv_timeout, 0, 0);
/*
* Set once the preparation of devices for a PM transition has started, reset
* before starting to resume devices. Protected by dpm_list_mtx.
@@ -584,6 +588,45 @@ static bool is_async(struct device *dev)
&& !pm_trace_is_enabled();
}
/**
* dpm_drv_timeout - Driver suspend / resume watchdog handler
* @data: struct device which timed out
*
* Called when a driver has timed out suspending or resuming.
* There's not much we can do here to recover so
* BUG() out for a crash-dump
*
*/
static void dpm_drv_timeout(unsigned long data)
{
struct device *dev = (struct device *) data;
printk(KERN_EMERG "**** DPM device timeout: %s (%s)\n", dev_name(dev),
(dev->driver ? dev->driver->name : "no driver"));
BUG();
}
/**
* dpm_drv_wdset - Sets up driver suspend/resume watchdog timer.
* @dev: struct device which we're guarding.
*
*/
static void dpm_drv_wdset(struct device *dev)
{
dpm_drv_wd.data = (unsigned long) dev;
mod_timer(&dpm_drv_wd, jiffies + (HZ * 3));
}
/**
* dpm_drv_wdclr - clears driver suspend/resume watchdog timer.
* @dev: struct device which we're no longer guarding.
*
*/
static void dpm_drv_wdclr(struct device *dev)
{
del_timer_sync(&dpm_drv_wd);
}
/**
* dpm_resume - Execute "resume" callbacks for non-sysdev devices.
* @state: PM transition of the system being carried out.
@@ -935,7 +978,9 @@ static int dpm_suspend(pm_message_t state)
get_device(dev);
mutex_unlock(&dpm_list_mtx);
dpm_drv_wdset(dev);
error = device_suspend(dev);
dpm_drv_wdclr(dev);
mutex_lock(&dpm_list_mtx);
if (error) {