Date: Mon, 9 Oct 2006 13:45:57 -0400 From: Jung-uk Kim <jkim@FreeBSD.org> To: freebsd-amd64@FreeBSD.org, John-Mark Gurney <gurney_j@resnet.uoregon.edu> Subject: Re: amd64 agp driver bug? Message-ID: <200610091346.02064.jkim@FreeBSD.org> In-Reply-To: <20061007214336.GJ793@funkthat.com> References: <20061007214336.GJ793@funkthat.com>
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On Saturday 07 October 2006 05:43 pm, John-Mark Gurney wrote: > 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... As you can see, this part of the documentation is very confusing. :-( I'll take care of it soon. Jung-uk Kim
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