Re: [PATCH v2 7/8] watchdog: starfive-wdt: Stop ping worker on system suspend

[Tzung-Bi Shih <tzungbi@kernel.org>]

On Thu, Nov 05, 2026 at 11:05:28AM -0800, Guenter Roeck wrote:
> When early_enable=1 is set and CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED is
> enabled, watchdog_register_device() starts the watchdog core hrtimer so the
> non-freezable watchdogd kthread worker periodically pings the hardware
> before userspace opens /dev/watchdog.
> 
> Because starfive_wdt_probe() does not call watchdog_stop_ping_on_suspend(),
> WDOG_NO_PING_ON_SUSPEND is not set and the watchdog core does not cancel
> its hrtimer and ping work across system suspend. After
> starfive_wdt_suspend() stops the counter and calls
> pm_runtime_force_suspend() to gate core_clk and apb_clk, WDOG_HW_RUNNING
> remains set; if the timer fires before starfive_wdt_resume() re-enables
> the clocks, watchdog_ping_work() invokes starfive_wdt_keepalive() with
> gated clocks and causes an unclocked MMIO bus fault.
> 
> Call watchdog_stop_ping_on_suspend() in starfive_wdt_probe() so the
> watchdog core cancels its ping timer and work in PM_SUSPEND_PREPARE before
> clocks are gated and resumes pinging in PM_POST_SUSPEND after clocks are
> restored.
> 
> Fixes: db728ea9c7be ("drivers: watchdog: Add StarFive Watchdog driver")
> Cc: Xingyu Wu <xingyu.wu@starfivetech.com>
> Cc: Ziv Xu <ziv.xu@starfivetech.com>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>