Surprising fact about STREAMS service modules

[Doug Gwyn]

In article <15167 at mimsy.UUCP> chris at mimsy.UUCP (Chris Torek) writes:
>Alas, some VAX hardware (and some other hardware) requires this sort of
>foolery.  The Qbus interrupt system is such that a device that is
>supposed to operate at IPL15 (such as a DHV11) may in fact interrupt at
>IPL17, if there is a device behind it on the bus that requests at BR7.

I thought the interrupt vector was supposed to establish the actual
kernel service IPL.  (Or was I thinking about some other system?)
Anyway, it would seem to be a good idea, given that the device drivers
seem to think they know what the "proper" IPL is supposed to be.