in this article
from the answer to the question
What are the constraints on user-mode drivers?
i get the feeling that all hardware that require interrupts require a kernel mode driver, hence all hardware on the PCMCIA bus would require a kernel mode driver, hence all Pnp devices require a kernel mode driver.
however scrolling down, i came across the folwloing answer to the question
What is the difference between a user-mode driver and an application?
and from it i understand that PnP devices can use user mode drivers, correct?