Hello,
well winfried has written the alsa-drivers for the new hdsp (the one with 64 in/out-channels), and i guess he fixed a lot of bugs with the old drivers. i am not sure, whether they will make it into the frist 2.6-kernel-release.
The latest patches (most of them) for the Hammerfall HDSP card was made by Thomas Charbonnel and who did a great work. The most of the patches was related to the mixer interface so that his helpers apps hdspload, hdspmixer and hdspconf (part of the alsa tools) work.
All patches (hopefully) have been applied to alsa-cvs now and therefore will be in 2.6.x next release (since the alsa-kernel tree in the alsa cvs is the part going to the kernel and the alsa-drivers for new applied driver).
Alsa native devices hw:0 ... have only the features the hardware offers, so pd -alsa dont work it is because the pd part has does not use NONINTERLEAVED, 32Bit and so on, but hwplug:x,x should work but will convert in the driver.
jack under linux is known to be the solution, but i also didnt got very stable solution,... Jack knows of hammerfall but is callback and also mixing and so on which is not needed all the time.
mfg winfried