Forum Discussion

JET60200's avatar
JET60200
Icon for Contributor rankContributor
4 years ago

How to stop or cancel an “Read/Write AVMM DMA operation” after it begins ?

Hi Intel experts,

Sometimes I saw Arria10 " PCIe AVMM DMA operation” would consume much more time than it's expected. Such as in normal case, the DMA operation will consume around “+35us” to complete its Task in the Descriptor Table, while in rare exceptional case, the DMA will consume around "+3000us" (or above) to complete a similar task in Desc table, which will break down our System Timing.

So I wonder whether there's any method to "Stop or Cancel" that current "exceptional" AVMM DMA operation, when we found it exceed EXPECTED duration. I check "AVMM User Guide", unfortnately found nothing about it.

If any one has some suggestion, that's great appreciated. Thanks a lot

@SengKok_L_Intel , please help if convenient, Thanks

5 Replies

  • SengKok_L_Intel's avatar
    SengKok_L_Intel
    Icon for Regular Contributor rankRegular Contributor
    4 years ago

    Hi,


    One possible solution is to generate the Secondary Bus Reset from the host. It is available at the Bridge Control register Bit 6.


    Regards -SK


    • JET60200's avatar
      JET60200
      Icon for Contributor rankContributor
      4 years ago

      " One possible solution is to generate the Secondary Bus Reset from the host. It is available at the Bridge Control register Bit 6. "

      -> Hello @SengKok_L_Intel ,

      Sorry for the delay , but which document describes the mentioned " Bridge Control Register " ?

      Pls help to point it out, so i could check it detailedly. thanks

      • SengKok_L_Intel's avatar
        SengKok_L_Intel
        Icon for Regular Contributor rankRegular Contributor
        4 years ago

        You can search the "secondary bus reset" or "bridge control register" from the PCIe spec.

  • SengKok_L_Intel's avatar
    SengKok_L_Intel
    Icon for Regular Contributor rankRegular Contributor
    4 years ago

    If further support is needed in this thread, please post a response within 15 days. After 15 days, this thread will be transitioned to community support. The community users will be able to help you with your follow-up questions.