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heeralk's avatar
heeralk
Icon for New Contributor rankNew Contributor
4 years ago

PCIe MCDMA Gen3x16 Simulation : D2H not fetching data as per descriptor size

Hi ,

I'm using Intel's Pcie MCDMA gen3x16.

For D2H descriptor , I'm requesting for 1600 bytes as my payload size. I have enabled Msi interrupt at the end of transfer. I see an issue that , the msix interrupt is coming after transfer of 1154 bytes itself. Can you help me resolve this issue.

Attached here is the screenshot of the waveform. the device has not issued eof , still msi interrupt has come.

Thanks and Regards

Heeral

5 Replies

    • heeralk's avatar
      heeralk
      Icon for New Contributor rankNew Contributor
      4 years ago

      Hi KhaiY ,

      Thanks for your response. So the device is suppose to give back to host 1600 bytes, that's why my d2h payload size is 1600 byte. So I have split into 4 descriptor as below :

      # rx desc addr 00000000000a0000 , size 512 , msix en bit 0 , descriptor count 0
      # rx desc addr 00000000000a0200 , size 512 , msix en bit 0 , descriptor count 1
      # rx desc addr 00000000000a0400 , size 512 , msix en bit 0 , descriptor count 2
      # rx desc addr 00000000000a0600 , size 64 , msix en bit 1 , descriptor count 3

      I have enabled msix only for the last descriptor. still I see the msix interrupt coming after 1154 bytes of data.

      One note :

      My device (ip ) which is giving the data is not giving it continously. it gives 1154 bytes continuously , then it gives the remaining bytes after 1.6us . I have captured my device data waveform in standalone test as below :

      The userguide doesnt mention if the data from device has to be continuous or not.

      Please help me resolve the issue.

      Thanks and Regards

      heeral

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

    Hi Heeral,


    In the latest waveform, there is no signal name. Could you share a waveform with signal name? Does this happen if you transfer a smaller d2h payload size or less than 1154 bytes?


    Thanks

    Best regards,

    KhaiY


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

    Hi,

    We do not receive any response from you to the previous question/reply/answer that I have provided. This thread will be transitioned to community support. If you have a new question, feel free to open a new thread to get the support from Intel experts. Otherwise, the community users will continue to help you on this thread. Thank you.


    Thanks

    Best regards,

    KhaiY