STRUCT WATCHDOG_DEVICE(9)

💖 NAME 💖

okay so this is struct watchdog_device, bestie — straight from the Kernel API Manual, section 9. It’s literally the structure that defines a watchdog device, and yes, she’s iconic. Periodt. 🎀✨

🎀 SYNOPSIS 🎀

no cap, here’s the whole struct exactly as it appears — do not touch the formatting, she’s sensitive:

       struct watchdog_device {
           int id;
           struct device *parent;
           const struct attribute_group **groups;
           const struct watchdog_info *info;
           const struct watchdog_ops *ops;
           const struct watchdog_governor *gov;
           unsigned int bootstatus;
           unsigned int timeout;
           unsigned int pretimeout;
           unsigned int min_timeout;
           unsigned int max_timeout;
           unsigned int min_hw_heartbeat_ms;
           unsigned int max_hw_heartbeat_ms;
           struct notifier_block reboot_nb;
           struct notifier_block restart_nb;
           struct notifier_block pm_nb;
           void *driver_data;
           struct watchdog_core_data *wd_data;
           unsigned long status;
         #define WDOG_ACTIVE             0       ;
         #define WDOG_NO_WAY_OUT         1       ;
         #define WDOG_STOP_ON_REBOOT     2       ;
         #define WDOG_HW_RUNNING         3       ;
         #define WDOG_STOP_ON_UNREGISTER 4       ;
         #define WDOG_NO_PING_ON_SUSPEND 5       ;
           struct list_head deferred;
        };

💅 Members 💅

okay bestie, let’s go member by member, because every field matters and we are not skipping a single one:

• id — The watchdog’s ID. (Allocated by watchdog_register_device.) 💖
• parent — The parent bus device. 🚌
• groups — List of sysfs attribute groups to create when creating the watchdog device. ✨
• info — Pointer to a watchdog_info structure. 📋
• ops — Pointer to the list of watchdog operations. 🛠️
• gov — Pointer to watchdog pretimeout governor. 👑
• bootstatus — Status of the watchdog device at boot. 🌅
• timeout — The watchdog device’s timeout value (in seconds). ⏳
• pretimeout — The watchdog device’s pre_timeout value. ⏰
• min_timeout — The watchdog device’s minimum timeout value (in seconds). 🥺
• max_timeout — The watchdog device’s maximum timeout value (in seconds) as configurable from user space. Only relevant if max_hw_heartbeat_ms is not provided. 🔥
• min_hw_heartbeat_ms — Hardware limit for minimum time between heartbeats, in milli-seconds. 💓
• max_hw_heartbeat_ms — Hardware limit for maximum timeout, in milli-seconds. Replaces max_timeout if specified. 💥
• reboot_nb — The notifier block to stop watchdog on reboot. 🔄
• restart_nb — The notifier block to register a restart function. 🫶
• pm_nb — The notifier block to stop watchdog on suspend and restart it on resume. 😴➡️🏃
• driver_data — Pointer to the driver’s private data. 🔐
• wd_data — Pointer to watchdog core internal data. 🧠
• status — Field that contains the device’s internal status bits. 📊
• deferred — Entry in wtd_deferred_reg_list which is used to register early initialized watchdogs. 🐣

🌸 Description 🌸

The watchdog_device structure contains all information about a watchdog timer device. That’s the whole vibe: one struct, all the watchdog tea. 🫖💅

The driver_data field may not be accessed directly. Nope, absolutely not, bestie — that’s a hard no. It must be accessed via the watchdog_set_drvdata and watchdog_get_drvdata helpers. That’s the rule, iykyk. 🚫🔑

🔥 SEE ALSO 🔥

• Kernel file ./include/linux/watchdog.h — go read it, it’s giving source-of-truth energy. 📖✨
• struct watchdog_ops(9) — the companion page, slay. 👯‍♀️

okay bye bestie 🫶 mwah 💋 — source/version footer says ./include/linux, date October 2026, and the manual title is struct watchdog_device(9). Slay and stay watched. 🌈✨