Date: Mon, 13 Oct 2008 05:40:20 -0700 From: Jeremy Chadwick <koitsu@FreeBSD.org> To: Gary Jennejohn <gary.jennejohn@freenet.de> Cc: freebsd-amd64@FreeBSD.org Subject: Re: how does the kernel go about mapping memory for amd64? Message-ID: <20081013124020.GA18797@icarus.home.lan> In-Reply-To: <20081013141556.7b7a0806@ernst.jennejohn.org> References: <20081013141556.7b7a0806@ernst.jennejohn.org>
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On Mon, Oct 13, 2008 at 02:15:56PM +0200, Gary Jennejohn wrote: > > I have a new mother board, a Gigabyte GA-MA78GPM-DS2H, which shows > really weird behavior under FreeBSD when I have 4GB of memory and a > PCI card plugged into it. > > With an Adaptec 29160 plugged in FreeBSD sees only 3GB and there is _no_ > memory mapped above 4GB. This seems like a bug in the BIOS. > > With no PCI card plugged in FreeBSD sees memory mapped above 4GB and > almost 4GB are available. > > Note that this board has graphics in the chipset (AMD 780G) which uses UMA > (128 MB) for the video buffer. > > This behavior leads me to believe that FreeBSD is only using the memory > mapping hints provided by the BIOS and is not sizing and mapping memory > itself. > > Is that correct? You might also try freebsd-hackers for this kind of thing, as it's pretty low-level. Does Linux and/or Windows exhibit the same problem? If so, I would open up a case with Gigabyte. This should be very easily reproducible, although I would not be surprised if they ask for you to send them your Adaptec controller. -- | Jeremy Chadwick jdc at parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |
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