fw/drivers/rtc: bound RSF sync wait in rtc_get_time_ms#1716
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The wait for RTC shadow-register synchronization spun forever if RSF
never set. On FIRM-3403 a wedged low-power domain left RSF stuck low,
so rtc_get_time_ms hung the system task and tripped the task watchdog
("stuck task" reboot 9 s after boot on v4.23.0).
Bound the wait at 1M iterations (~40-200 ms depending on HCLK, vs
~0.5 ms genuine sync time) and fall back to the last-synced shadow
values, degrading to stale time instead of a watchdog reboot loop.
The timeout is logged once; the guard flag is set before logging
because PBL_LOG timestamps re-enter rtc_get_time_ms.
Related to FIRM-3403.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Signed-off-by: Joshua Jun <lets@throw.rocks>
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@rabbitsaviola please check |
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It may be worth panicking if this happens, because a bad RTC can then cause all sorts of random bugs that are very difficult to trace. But let's wait for @rabbitsaviola feedback. |
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The wait for RTC shadow-register synchronization spun forever if RSF never set. On FIRM-3403 a wedged low-power domain left RSF stuck low, so rtc_get_time_ms hung the system task and tripped the task watchdog ("stuck task" reboot 9 s after boot on v4.23.0).
Bound the wait at 1M iterations (~40-200 ms depending on HCLK, vs ~0.5 ms genuine sync time) and fall back to the last-synced shadow values, degrading to stale time instead of a watchdog reboot loop. The timeout is logged once; the guard flag is set before logging because PBL_LOG timestamps re-enter rtc_get_time_ms.
Related to FIRM-3403.