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DM3730 SGX Cold Temperature Issue

Other Parts Discussed in Thread: DM3730

Hello,

We are using a Torpedo module from LogicPD that incorporates the DM3730 processor.  We are using a specially developed operating system and an SGX530 driver that was purchased from Imagination Technologies and modified to work with our operating system.  This implementation has been used in many applications without issue but, during testing of one of our products at cold temperature (around -40C), we’ve found one Torpedo module on which the SGX GPU is requesting hardware recovery.  We are trying to determine the root cause of this issue.  Here are the specifics of the request our SGX driver is getting from the hardware:

In the SGX ISR handler, we are getting the following flag set in the interrupt status register:
PVRSRV_USSE_EDM_INTERRUPT_HWR                (1UL << 0)           /*!< EDM requesting hardware recovery */

We would like to know if there are any known reasons why cold temperature would cause this behavior.  Also, we would like to acquire all information relating to the scenarios in which the GPU will make this request.

Kris Stabley
L-3 Communications
Phone:  (614) 825-2287

  • Hi Kris,

    If the problem appears only at extremely low temperatures (around -40C) I suggest you to check the power supply voltage and all line levels of the chip. This temperature is the lower limit of the operating range of the chip and it is possible to work unstable. Also it is necessary to check the operating temperature range all elements on the board and measure its parameters at this temperature whether they match to their specifications.

    BR

    Tsvetolin Shulev

  • Tsvetolin,

    Thanks for the information! We are in the process of evaluating the power supplies on our hardware as well as those on the LogicPD Torpedo module. During our investigation, a question has come up regarding the operation of the SGX GPU when it has requested a hardware recovery.  The question is, what would be the effects if software were to ignore this recovery request and do nothing.  We’re going to perform this test to see what occurs, but would like some further guidance as to what the expected result would be.

    If the effects are specifically known and we find them to be acceptable for our application, we may choose to proceed with this approach, otherwise, we’ll continue our investigation.

    Kris Stabley
    L-3 Communications
    Avionics Systems, Inc.
    Phone:  (614) 825-2287
  • New Finding:

    “The fault record from from our most recent run resulted in no GPU requested reset faults.  However, there was one reset fault due to the Render thread stopping.  This indicates that the GPU stopped running altogether.  The GPU must have encountered a fault severe enough to cause its firmware to stop running.    

  • Hi Jeff,

    Could you confirm that this problem appears only at extremely low temperature (- 40 C) and the problem not appear at room temperature?

    BR

    Tsvetolin Shulev

  • Tsvetolin . . . I am confirming the problem has only been observed at cold temperature, at or near -40 C on this particular LogicPD Torpedo module.

     

    Jeff Golden

  • Jeff,

    The problem is not observed on other board but seems that it is a hardware issue which appears at the border of the operating temperature range of the DM3730.

    BR

    Tsvetolin Shulev