Date: Tue, 20 May 1997 09:51:29 -0700 (MST) From: Terry Lambert <terry@lambert.org> To: msmith@atrad.adelaide.edu.au (Michael Smith) Cc: dfr@nlsystems.com, se@FreeBSD.ORG, msmith@atrad.adelaide.edu.au, current@FreeBSD.ORG Subject: Re: Backwards compatibiliy for isa_driver Message-ID: <199705201651.JAA01507@phaeton.artisoft.com> In-Reply-To: <199705201317.WAA02812@genesis.atrad.adelaide.edu.au> from "Michael Smith" at May 20, 97 10:47:07 pm
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> > > If I remember correctly, ISA port addresses are not fully > > > decoded on many cards, and thus we have to expect a card > > > to be visible multiple times in the address space. There > > > should be a way to encode the address range. (I'm using a > > > ln2range struct element for this purpose in the PCI code.) > > > > Ohhh. Thats nasty. Does this mean that reserving a port range for those > > cards will also have to reserve all the address where the ports are > > visible? > > It means that "ISA" instances of a device can only be expected in the > range 0x100-0x400, but that if the motherboard chipset is broken or > old, probes at higher multiples of the device's address may still show > it up. This is not normally a problem, as you only go above there for > EISA/PCI devices. This is not a motherboard problem. This is a card line decoding problem. And yes, many, many modem cards and older 8/16 bit ethernet cards have this flaw. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.
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