Are legacy/INTx interrupts known to work on connectx-4 adapters?

I’ve written a driver for OpenBSD that supports connectx-4+ ethernet (equivalent to the mlx5 driver), based on the Programming Reference Manual. While writing this I attempted to use legacy interrupts as we don’t have MSI-X on all hardware platforms, and I never got it to work. MSI-X works as expected on platforms where it’s available.

The PRM refers to legacy interrupt support in a few places, and there doesn’t seem to be any reason it wouldn’t work, but I notice the mlx5 driver will only use MSI-X and will fail to initialize if that doesn’t work. Are legacy interrupts known to work in some configuration?

Hello Jonathan,

Base on our internal datasheet, INTx interrupts is not supported.

Compatibility

• Advanced Error Reporting (AER)

• Access Control Services (ACS)

• Downstream Port Containment (DPC)

• MSI Interrupt support

• RX margin/link maintenance support

Also we had provide freebsd driver, and open source to freebsd. I think more design in issue you can though freebsd community.

https://svnweb.freebsd.org/base?view=revision&revision=347325

And some IC and internal design is not public, you can consult local sales and FAE get design in support.