On Wed, Apr 10, 2024 at 12:28:44AM +0800, PeterYin wrote: [ ... ] > > Hi Guenter, > Could you help me understand the definition of WDIOF_CARDRESET in the > kernel? If it resets the CPU, should all values be reset to default? Should Documentation/watchdog/watchdog-api.rst says: "Card previously reset the CPU" This is a bit historic and was probably defined when watchdogs were not typically integrated. The appropriate description, applied to current watchdog devices, would be something like "The most recent reset was triggered by this watchdog". Not sure I understand "If it resets the CPU...". It doesn't _do_ anything, it just reports if the most recent reset was triggered by the watchdog. > we check the POR (RstPwr Power on reset SRST# flag) flag in SCU 0x74 > register bit 0 in ast2600? > Only if it indicates that the most recent reset was triggered by the watchdog. Guenter