Date: Sun, 28 Sep 1997 11:04:56 -0700 (PDT) From: Alex <garbanzo@hooked.net> To: Mike Smith <mike@smith.net.au> Cc: Tony Overfield <tony@dell.com>, Terry Lambert <tlambert@primenet.com>, hackers@FreeBSD.ORG Subject: Re: INB question Message-ID: <Pine.BSF.3.96.970928110415.620B-100000@zippy.dyn.ml.org> In-Reply-To: <199709280919.SAA05487@word.smith.net.au>
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On Sun, 28 Sep 1997, Mike Smith wrote: > > At 02:44 PM 9/19/97 +0000, Terry Lambert wrote: > > >> > Yeah; that's why I picked the extended MCA DMA ports for the detect; > > >> > that, and I can do the probe non-destructively, with the expectation of > > >> > a 0 bit in my data and no hardware configuratio changes resulting. > > >> > > >> Where is the port exactly? ie. is it likely to be sat on or masked > > >> over by an ISA device? > > > > > >Port 0x18 is the control, and port 0x1A is the data. > > > > Port 0x18, on many systems, is an alias of port 0x08, which is > > the read-only DMA status register and the write-only DMA command > > register. Likewise, port 0x1A is often an alias of the write-only > > port 0x0A DMA mask register. > > Eep. That's not so good then. Now you're back; do *you* know how to > identify an MCA machine uniquely? >From the NetBSD/MCA page: "MCA bus detection is by checking certain bits of MCA adapter setup register at port 0x96: not sure if this is the best way to do it." - alex
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