Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cornell!uw-beaver!rice!sun-spots-request
From: jvc!jonathan@uunet.uu.net (Jonathan Hue)
Newsgroups: comp.sys.sun
Subject: spurious interrupts
Keywords: Hardware
Message-ID: <480@jvc.UUCP>
Date: 21 Apr 89 09:56:12 GMT
Sender: usenet@rice.edu
Organization: JVC Laboratory of America
Lines: 15
Approved: Sun-Spots@rice.edu
Original-Date: 31 Mar 89 23:17:38 GMT
X-Sun-Spots-Digest: Volume 7, Issue 233, message 14 of 14

Why do all of our Suns spit out "spurious level X interrupt" kernel
printfs?  (Sun-3/[12]60, SunOS 3.5)

We see these whenever we rewind the 1/2" tape drive (Fujitsu on a Xylogics
472), which seem to be harmless, and sometimes when using a National
Instrments GPIB controller (connected to an Eikonix scanner, using their
driver).  These aren't harmless, as the machine dies soon afterwards,
usually due to a kernel bus error.

I think I know what a spurious interrupt is, it's when something tugs on
IRQ[1-7], and the CPU performs an interrupt acknowledge cycle and doesn't
see DSACK[01], so it gets a bus error.  I'm curious why they occur, it
seems like a hw bug on someone's part.

-Jonathan	uunet!jvc!jonathan