Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cornell!uw-beaver!blake!ogccse!littlei!omepd!psu-cs!kirkenda
From: kirkenda@psu-cs.UUCP (Steve Kirkendall)
Newsgroups: comp.os.minix
Subject: Re: Hard drives on ST
Message-ID: <1630@psu-cs.UUCP>
Date: 11 Feb 89 03:50:35 GMT
References: <961@dlhpedg.co.uk> <393@lzaz.ATT.COM> <2086@netmbx.UUCP>
Reply-To: kirkenda@psu-cs.UUCP (Steve Kirkendall)
Organization: Dept. of Computer Science, Portland State University; Portland OR
Lines: 19

I haven't seen anybody posting any news, good or bad, about using Minix-ST
with older Supra hard drives.  Not for a while, anyway.  Did we all figure
it out simultaneously about 6 weeks back, or what?

Basically, the problem is that the older Supra board send extra interrupts
after the DMA transfer is complete.  This either causes the kernel to print
"dma interrupt discarded" (a minor nuisance) or to panic when the hard disk
driver task received a message from -1, which is hardware.

I got my older Supra to work with Minix simply by bypassing that code.
(I commented out the "dma interrupt discarded" message in stdma.c, and
changed the panic() in stwini.c into a continue statement.)  I have been
using it quite heavily for several weeks now, with no problems at all.

If anybody out there knows any reason why I would run into grief by ignoring
those extra interrupts, PLEASE TELL ME!
-- 
"If I seem insensitive to what you're going through,
	keep in mind that's the way I am." -- Mr. Spock