Forum Discussion

Mikhail_a's avatar
Mikhail_a
Icon for Occasional Contributor rankOccasional Contributor
5 months ago

Agilex-7 MSI-X missing om AXI MCDMA for PCIe

Hi! We are using AGIB023R18A1E1VC device and AXI MCDMA for PCIe IP core. We set it to MCDMA+BAS+BAM mode as we want to use MSI-X interrupts. Our driver register for example 2 MSI-X interrupts in Lin...
Pcie
Wincent_Altera's avatar
Wincent_Altera
Icon for Regular Contributor rankRegular Contributor
5 months ago

Hi,

Based on your description, you have correctly configured the hardware and Linux driver for MSI-X, and lspci confirms MSI-X is enabled with available vectors.
However, the interrupts are not seen on the host. 

I would suggest to check 

  • MSI-X table mapping
    • Ensure the BAR (Base Address Register) specified for the MSI-X vector table (e.g., BAR=0 at offset 0x00100000) is correctly mapped and accessible by both the FPGA and the Linux OS.
    • If the mapping is off, MSI-X table writes may not trigger interrupts.
  • Masked vectors
    • MSI-X must remain enabled (Enable+ in lspci).
    • Vectors must be unmasked (Masked- in lspci). If vectors are masked in the device or host, interrupts are blocked.
    • Confirm that the device or driver does not inadvertently mask vectors after initialization.
  • Driver initialization issues,
    • Maps the MSI-X vectors properly
    • Registers the interrupt handlers correctly
    • Binds the expected number of vectors (matching what is requested)

Regards,
Wincent