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Commit 2501b015 authored by Sebastian Reichel's avatar Sebastian Reichel Committed by Wim Van Sebroeck
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watchdog: core: add option to avoid early handling of watchdog 



On some systems its desirable to have watchdog reboot the system
when it does not come up fast enough. This adds a kernel parameter
to disable the auto-update of watchdog before userspace takes over
and a kernel option to set the default. The info messages were
added to shorten error searching on misconfigured systems.

Signed-off-by: default avatarSebastian Reichel <sebastian.reichel@collabora.co.uk>
Reviewed-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarWim Van Sebroeck <wim@iguana.be>
parent 166fbcf8

drivers/watchdog/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -46,6 +46,17 @@ config WATCHDOG_NOWAYOUT 
	  get killed. If you say Y here, the watchdog cannot be stopped once

	  it has been started.



config WATCHDOG_HANDLE_BOOT_ENABLED

	bool "Update boot-enabled watchdog until userspace takes over"

	default y

	help

	  The default watchdog behaviour (which you get if you say Y here) is

	  to ping watchdog devices that were enabled before the driver has

	  been loaded until control is taken over from userspace using the

	  /dev/watchdog file. If you say N here, the kernel will not update

	  the watchdog on its own. Thus if your userspace does not start fast

	  enough your device will reboot.



config WATCHDOG_SYSFS

	bool "Read different watchdog information through sysfs"

	help

drivers/watchdog/watchdog_dev.c

+16 −3
Original line number Diff line number Diff line
@@ -80,6 +80,9 @@ static struct watchdog_core_data *old_wd_data; 


static struct workqueue_struct *watchdog_wq;



static bool handle_boot_enabled =

	IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED);



static inline bool watchdog_need_worker(struct watchdog_device *wdd)

{

	/* All variables in milli-seconds */
@@ -956,9 +959,14 @@ static int watchdog_cdev_register(struct watchdog_device *wdd, dev_t devno) 
	 * and schedule an immediate ping.

	 */

	if (watchdog_hw_running(wdd)) {

		if (handle_boot_enabled) {

			__module_get(wdd->ops->owner);

			kref_get(&wd_data->kref);

			queue_delayed_work(watchdog_wq, &wd_data->work, 0);

		} else {

			pr_info("watchdog%d running and kernel based pre-userspace handler disabled\n",

					wdd->id);

		}

	}



	return 0;
@@ -1106,3 +1114,8 @@ void __exit watchdog_dev_exit(void) 
	class_unregister(&watchdog_class);

	destroy_workqueue(watchdog_wq);

}



module_param(handle_boot_enabled, bool, 0444);

MODULE_PARM_DESC(handle_boot_enabled,

	"Watchdog core auto-updates boot enabled watchdogs before userspace takes over (default="

	__MODULE_STRING(IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED)) ")");