watchdog_set...hw_keepalive(9)

💖 NAME 💖

watchdog_set_last_hw_keepalive — okay so this one sets the last HW keepalive time for a watchdog, bestie ✨ (yes it's a whole mouthful, we love her anyway)

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🎀 SYNOPSIS 🎀

int watchdog_set_last_hw_keepalive (struct watchdog_device *wdd ,
unsigned int last_ping_ms );

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🌸 ARGUMENTS 🌸

• wdd — the watchdog device itself, like the actual struct, the main character 👑
• last_ping_ms — time since last HW heartbeat ⏱️ so basically "how long ago did this thing last get a lil ping"

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🦋 DESCRIPTION 🦋

So this function adjusts the last known HW keepalive time for a watchdog timer, no cap. Why do you even need it?? Okay so picture this: the watchdog is already running by the time the probe function gets called, and it literally can't be pinged immediately 😭 — that's the exact situation this exists for.

Two things you gotta know, and I'm being so serious rn:

This function must be called immediately after watchdog registration, and min_hw_heartbeat_ms must be set for this to be useful. Like, both of those. Periodt. 💅

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⭐ RETURN ⭐

0 if successful, error otherwise. That's it, that's the vibe check 🙈 (zero equals slay, anything else equals not slay)

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🌈 SEE ALSO 🌈

Kernel file ./drivers/watchdog/watchdog_dev.c, plus the whole friend group:

• watchdog_ping(9)
• watchdog_start(9)
• watchdog_stop(9)
• watchdog_get_status(9)
• watchdog_set_timeout(9)
• watchdog_set_pretimeout(9)
• watchdog_get_timeleft(9)
• watchdog_ioctl_op(9)
• watchdog_write(9)
• watchdog_ioctl(9)
• watchdog_open(9)
• watchdog_release(9)
• watchdog_cdev_register(9)
• watchdog_cdev_unregister(9)
• watchdog_dev_register(9)
• watchdog_dev_unregister(9)
• watchdog_dev_init(9)
• watchdog_dev_exit(9)

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okay that's the whole page, you ate that 🫶 this iconic lil doc lives in ./drivers/watchdog and it's dated October 2026 — mwah, go ping something 💜🧚