Date: Sat, 7 Oct 2006 14:43:36 -0700 From: John-Mark Gurney <gurney_j@resnet.uoregon.edu> To: freebsd-amd64@FreeBSD.org Subject: amd64 agp driver bug? Message-ID: <20061007214336.GJ793@funkthat.com>
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I was looking at the agp driver and the BIOS and Kernel Developer's
Guide, and noticed that it appears we program the page register
incorrectly...
Currently we do, in sys/pci/agp_amd64.c:
sc->gatt->ag_virtual[offset >> AGP_PAGE_SHIFT] = physical;
but according to Table 38 in the guide, it looks like it should be:
sc->gatt->ag_virtual[offset >> AGP_PAGE_SHIFT] =
(physical & 0xfffff000) | ((physical >> 28) & 0xff0) | 1;
To support physical addresses above 4G...
Has anyone used AGP w/ >4GB of memmory? I'm also puzzled by the fact
that the guide says to set bit 0, but we don't do that...
--
John-Mark Gurney Voice: +1 415 225 5579
"All that I will do, has been done, All that I have, has not."
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