[linux-audio-user] rme hdsp latency and irq settings

I've been running a RME hdsp multiface2 with pci on the PlanetCCRMA low latency kernel for a couple months now, and while it runs nice, I can't get the latency in Pd below about 20ms. If I set anything lower, there are dropouts. I've messed around with the Pd settings a bit, but I haven't touched any system settings because I'm confused by the stats of my soundcard. lspci -v tells me the hdsp card is on irq 187 and it has 255ms latency. According to all the documentation I have seen (which is all at least a couple years old, most the time around 2000), neither of these numbers should be possible. I think the low latency kernel, with "realtime preemption patch by Ingo Molnar", is messing with these, but I really don't know. Does anyone know anything about what the hdsp's irq and latency settings should be on a realtime linux system? Thanks for all help, Richie