[WP760x][SW] Watch Dog Timer for native Linux

Legato Linux distribution (Yocto project)
1

Question:
Does WP760x have Watch Dog Time for native Linux?

Back Ground:
Generally, native Linux have WDT under /dev/watchdog.
So we would like to know whether WP760x have such WDT.

2

No, I don’t see there is /dev/watchdog.
Please use the legato watchdog API.

3

Hi, jyijyi
I have an additional question about watchdog API.

Question:
Does watchdog legato API work either Software watchdog or Hardware watchdog?

Back Ground:
If Linux distribution is freeze, I would like to know whether watchdog legato API can be worked in this case.

4

It says " The daemon monitors app’s processes for hangs or freezing and if the process doesn’t “kick” the watchdog daemon in a specified time (the default is 30 seconds ), the watchdog signals the Supervisor to perform a specified action.

That means the reboot action is done by supervisor.

5

Hi, jyijyi

If “Legato” system was freeze, it seems that legato API watchdog can be worked to operate the specific process to Supervisor.
However I would like to know whether WP can be worked watchdog if “Yocto distribution” was freeze.
I think legato API watchdog could not be covered in the case of freezing Yocto distribution.

I considered whether our system add external watchdog, that’s why I asked it.

6

From here, it says the supervisor is run on legato system:

BTW, when you say yocto freezes, how can we simulate this situation ?

7

Hi, jyijyi

https://partnercommunity.sierrawireless.com/s/case/5001M00001PGMDrQAP/00935522-wp7605hw-behavior-of-application-core-if-telecom-core-is-hangup
(Sorry this is SFDC for only our account)

According to the above SFDC, you said that module was reboot both telecom core and modem core if the module was hang-up.
I think the recovery sequence of legato and yocto distribution in that case.

“Yocto freezes” means to be supposed such module hang-up situation.
I would like to know which areas inside of WP can be recovered automatically and whether legato API watch is worked in this module hang-up situation.

8

I just have a look on the AT command user guide, there is a command AT!MCUWATCHDOG which is using the on-board MCU watchdog.
It seems we already have a hardware watchdog there.
Please create another SF ticket so that we will double confirm internally.

BTW, are you asking about WP7605 only?
I just check product technical specification, WP7605 belongs to Group B variants which do not have MCU.
But other variants WP7601, WP7603, WP7607, WP7608, WP7609, there is on-board MCU.

9

Hi, jyijyi

I issued SFDC#00945564, please check it.