Date: Thu, 23 Oct 2008 04:04:22 +1000 (EST) From: Peter Grehan <grehan@freebsd.org> To: Nathan Whitehorn <nwhitehorn@freebsd.org> Cc: freebsd-ppc@freebsd.org Subject: Re: graphics on G4 Message-ID: <20081023040422.EKQ11018@dommail.onthenet.com.au>
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Hi Nathan, >One thing that worries me about our PMAP layer could cause >this. This machine has a lot of RAM. What happens if we have >physical or device memory in the same range as kmem VAs? >It seems like trying to modify it through the BAT map (as >zero/copy page, /dev/mem and friends do) will overwrite >random bits of KVA instead... Apple h/w seems to use 0-2G for RAM, and 2G and up for MMIO. G5's can then use > 4G for additional RAM. I've not seen a system that has a conflict with the 2 seg's used for KVA, but I wouldn't say it's not possible. Justin - can you drop into OFW, do a 'dev screen' and '.properties', and list the 'address' property ? later, Peter.
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