i.MX6D Watchdog Timer Timing Out Too Fast

[leoschwab]

We have an i.MX6D-based board, and we are trying to use the watchdog timer to reboot the system in case of inactivity.  The device enumerates correctly during boot:

imx2-wdt 20bc000.wdog: IMX2+ Watchdog Timer enabled. timeout=60s (nowayout=1)

However, when we measure it, the watchdog reboots the system after 25 seconds, not after 60 seconds.  The register WDOG1_WCR contains the value 0x779F, which is consistent with a 60-second timeout.  We're pretty sure it's nothing else that's rebooting the system since, if we tickle /dev/watchdog every 20 seconds, the system does not reboot.

Has anyone seen this before?  Is it possible we've messed up on setting up some of the clocks?

[sebastian_reich]

Hi,

I have run into the same issue. Did anyone find the root cause in the meantime?

-- Sebastian

[sebastian_reich]

Hi,

I figured out, that the 32khz clock did run much faster than it should by using the SNVS RTC:

# cat /sys/class/rtc/rtc1/name
snvs_rtc 20cc000.snvs:snvs-rtc-lp
# cat /sys/class/rtc/rtc1/since_epoch ; sleep 60 ; cat /sys/class/rtc/rtc1/since_epoch
5534
5698
# echo "5698-5534 = 164 => 32khz clock was almost 3x faster than it should be"‍‍‍‍‍‍

In my case the imx6dl is mounted on a off-the-shelf system on module and the issue was fixed by a new revision of the custom carrier board. I do not know what carrier board change caused/fixed the issue. My guess is, that there were some power glitches.

-- Sebastian

[benoitmoffet]

Hi Leo,

Did you figure what is the issue by yourself? I am experiencing the same issue and nobody at Freescale seems to understand it.

Regards,

[leoschwab]

Nope.  The issue does seem to have "gone away" in that watchdog timeouts now take the expected amount of time, but I've no idea what we changed/fixed to make that happen.

[igorpadykov]

Hi Leo

you can add WDOG initialization ar very beginning of

processor start-up, say in uboot lowlevel_init.S and check.

Best regards

chip

[leoschwab]

ERROR: Non-sequitur (Response bears no relation to the question asked).