Date: Fri, 19 Jun 98 15:52:56 -0400 From: cr@jcmax.com (Cyrus Rahman) To: smp@FreeBSD.ORG Subject: Re: S3 video cards Message-ID: <9806191952.AA19235@corona.jcmax.com>
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> I have just changed the videocard once again in one of those machines to > an old Diamond Viper PRO video (P9100 based) and it hasn't failed yet, in > fact I'm writing this in a xterm on it.... > I have a wierd feeling that these boards don't like S3 cards, all the > others we've tried where different vinatage S3 boards. > Well we'll see what happens, but it hasn't that stable with any of the > other cards... > Anybody else seen problems with S3 cards ?? After extensive testing, we concluded that S3 cards (and all derived chipsets, at least as of one year ago) don't address memory over 64mbytes correctly. So they do trash your os if you install them and use X. We tried all sorts of variants last year, and called the manufacturers of various S3 cards to see if they had new bios's for their boards to fix the problem. They advised us that it wasn't their fault, because the chips themselves were defective and they couldn't work around it. The problem was not confined to FreeBSD - it occurred on SCO as well. Perhaps Windows95 and NT have some workaround like a bounce buffer, but then again it sounds as if it didn't work on those platforms for you. And the card manufacturers wouldn't have already known about the problem anyway unless it occurred on Microsoft OS's. The cards will perform quite reliably if you keep less than 64mbytes on the board. And I doubt the problem has anything to do with the motherboard. Since that time we've avoided S3 chips. There are plenty of cheap alternatives that work well. So the moral of the story is: Using an S3 card with more than 64mbytes of memory will crash your system as soon as you start DMA'ing memory around by raising and lowering windows in X. Those funny looking areas that should have been solid black are kernel pages, and your buffer cache is now black with a 10 point Courier font (actually, we never saw file corruption, but we worried about it during testing). Let me know if this sounds like it could be your problem. Cyrus To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message
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