Linux DAW and an interface's onboard DSP

I am generally satisfied with using a Linux DAW like Reaper with Class Compliant audio interfaces. Everything works as expected. However, I am left wondering what I would be missing if I had an audio interface with onboard DSP. If I understand it correctly, onboard DSP is controlled by the proprietary software provided with the interface. As far as I know, there is as yet no such proprietary software that runs on Linux. So when I use Reaper with such an interface on Linux, does it engage the DSP at all? I'd really like to know if I'm missing out on that. Would be happy to hear from the experts here. TIA.