Date: Thu, 09 Nov 2000 10:41:33 -0700 From: "Justin T. Gibbs" <gibbs@scsiguy.com> To: Terry Lambert <tlambert@primenet.com> Cc: current@FreeBSD.org Subject: Re: vx driver patch Message-ID: <200011091741.eA9HfXa88677@aslan.scsiguy.com> In-Reply-To: Your message of "Thu, 09 Nov 2000 16:59:50 GMT." <200011091659.JAA21072@usr08.primenet.com>
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>> >What about EISA/VL or EISA/PCI systems? >> >> What about them? PCI devices are supposed to be found via PCI configuration >> space access. Even in these machines where a PCI card can be falsly >> probed as an EISA card, the standard PCI configuration mechanism works >> to correctly find PCI devices. VL cards are identified using ISA probe >> techniques in all cases I'm aware of. It just turns out that the 2842 >> uses a scheme that is very similar to that of an EISA card. > >As a backgrounder for other-than-Justin, Adaptec has a habit of >making multipurpose ROMs that sit on different types of devices, >so that they don't have to maintain multiple images. It's the >EISA stuff in these ROMs that causes a non-EISA BIOS based EISA >probe to incorrectly identify them as EISA. This is not correct. You are making this all much more confusing than it is. The 2842 will not be identified as an EISA device by the system BIOS or any other OS but FreeBSD. This is because you must *write* to the "EISA like" ID registers prior to reading them in order for them to return somthing other than 0. So, if our EISA probe stops poking the ID registers prior to reading them, the 2842 will not be seen. Secondly, there are some PCI systems that lack EISA slots entirely, but map device register space in traditionally EISA slot address ranges. Some of the aic78xx cards just happen to have registers in these locations that have values that satisfy an EISA probe. Of course, you're not supposed to be poking them in this way once the card is setup and, should the EISA code honor address reservations made by the system, as well as whether an EISA mainboard controller is found, these conflicts just wouldn't happen. All other VLB cards I know of look just like their ISA counterparts from a probe perspective. They shouldn't enter into this discussion. -- Justin To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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