Date: Thu, 30 Sep 2004 10:03:45 -0600 From: Scott Long <scottl@FreeBSD.org> To: Claus Guttesen <cguttesen@yahoo.dk> Cc: freebsd-current@FreeBSD.org Subject: Re: unable to install beta6 [amd64] on Dell 2850 with 4 GB RAM,workaround Message-ID: <415C2E61.8070904@FreeBSD.org> In-Reply-To: <20040930120946.26047.qmail@web14107.mail.yahoo.com> References: <20040930120946.26047.qmail@web14107.mail.yahoo.com>
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Claus Guttesen wrote: >>The AMR driver cannot handle >4GB of RAM. Even >>though you only have >>4GB, your chipset is remapping part of it to the >> >>>4GB region. The >> >>driver incorrectly interfaces with busdma and cannot >>handle this >>scenario very well. The panic is to be expected. >>You can verify >>this by setting the tunable 'hw.physmem' in the >>loader to some >>value under 4GB to artifically limit the amount of >>RAM that the OS >>sees. > > > Added hw.physmem=4G to /boot/loader.conf and it seems > to solve the issue. Dmesg now tells me that I have > > real memory = 3489398784 (3327 MB) > avail memory = 3367739392 (3211 MB) > > It seems that it does ignore some RAM, but is this the > correct behaviour? > > Without hw.physmem I get > > real memory = 5100273664 (4864 MB) > avail memory = 4125847552 (3934 MB) > > So it appears to perform an incorrect probing of > memory. > > Thank you. > Claus > That's not always the case. The system might be excluding a large part of the address space for some reason and mapping the RAM around it. Can you send a verbose dmesg to me in private? Scott
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