Comet Lake Q470 Linux WDAT Watch Dog TRLD question

[KLin]

Hello,

  We enabled WDAT in the Q470 board BIOS.  In Windows it worked fine however in Linux we notice when wdat_wdt is loaded or when we change TTMR time, the TRLD counter does not get reloaded. It always counts down from whatever is in TRLD.  We have to write to TRLD to force it to reload.  We are using kernel 5.4 and 5.10 main line from Ubuntu.  Is there a special setting in ACPI table or PCH register we need to set for TRLD to reload when driver is loaded or when TTMR is changed.?

Please advise

Thanks

Kevin     

[Steven_Intel]

Hello KLin,

Thank you for posting on the Intel® communities.

In order to better assist you with this concern, please provide the following information:

- Full model of processor used in the system.

- Download the Intel® System Support Utility for Linux: https://www.intel.com/content/www/us/en/download/18895/26735/intel-system-support-utility-for-the-linux-operating-system.html? And attach the file to your reply.

I look forward to hearing from you.

Regards,

Steven G.

Intel Customer Support Technician.

[Steven_Intel]

Were you able to check the previous post?

Let us know if you still need assistance.

Best regards,

Steven G.

Intel Customer Support Technician.

[KLin]

Hello Steven,

  The CPU  is Celeron G5900E

  Attached is the output from ssu.sh.  Should you have question please let me know.

  here is how we test

•   load Linux WDAT_WDT driver - sudo modprobe wdat_wdt
•   starts watchdog - echo 1 | sudo tee /dev/watchdog 
•   wait 2 seconds and reset WDT - sleep 2 && echo 1 | sudo tee /dev/watchdog 

  After reset WDT time, we read TRLD and TTMR.  To our surprise, TRLD does not reset and is still counting down from preset value which is 4 per Intel spec.  The system reboots much sooner than TTMR time.  We also notice if we keep the pet interval, for lack of better term, to 1 sec or below, the TRLD eventually gets reloaded to TTMR value.  However the reload timing is random.   This is really puzzling us.  

  We look at our WDAT table in ACPI but cannot not find any problem. 

  If you have any insight how to work on this, please let us know. 

  Regards

  Kevin

P.S. same problem also happens in Intel N4200 Apollo Lake platform using WDAT_WDT driver. 

[Jaime_Lizarme]

Hi Kevin,

I see that you are running your WDT application on Linux, so I need to clarify that CML supports the following distributions; however, its OS and drivers support is given through each community channel:  Ubuntu*, SuSe, Redhat* Enterprise, Wind River* and Yocto Project.

See the following links where you can submit your question in case you are using any of these distributions:

https://ubuntu.com/community

https://www.yoctoproject.org/community/

Best regards,

Jaime L.

Intel Customer Support Engineer

[Steven_Intel]

Hello KLin,

Thank you for your response.

In order to better assist you, I will move this thread to the embedded community support. The team in charge will get back to you soon.

Please feel free to reply if you have any concerns.

Regards,

Steven G.

Intel Customer Support Technician.