Messages in this thread | | | Date | Wed, 16 Jun 1999 02:58:12 -0700 | From | "H. Peter Anvin" <> | Subject | Re: K6-2 MTRR Problem |
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Richard Gooch wrote: > > H. Peter Anvin writes: > > Followup to: <199906160823.SAA04602@vindaloo.atnf.CSIRO.AU> > > By author: Richard Gooch <rgooch@atnf.csiro.au> > > In newsgroup: linux.dev.kernel > > > > > > Michael McLinn writes: > > > > > > > > It seems something isn't right with MTRR support for the K6-2, > > > > > > > > I have a K6-2 450, running 2.2.10. > > > > > > > > When I boot, there is a /proc/mtrr, but it is empty. > > > > > > > > When I > > > > echo "base=0xe8000000 size=0x10000000 type=write-combining" >| /proc/mtrr > > > ^^^^^^^^^^ > > > > > > So you have 256 MiB of RAM on you graphics card? Where can I buy one? > > > > The standard AGP aperture is 256 MiB; doesn't mean that the card > > actually has that much. > > Ah. How gross. > > > However, please note that the base address (0xe8000000) and the size > > (0x10000000) are incompatible! > > Indeed! So the AGP spec doesn't say anything about base address > increments? It would seem prudent for them to revise that part of the > PCI spec too... >
AGP uses PCI base registers to assign the base of its window. Accordingly, the data Michael McLinn put in are simply bogus: (base & (size-1)) must be 0.
-hpa
-- "The user's computer downloads the ActiveX code and simulates a 'Blue Screen' crash, a generally benign event most users are familiar with and that would not necessarily arouse suspicions." -- Security exploit description on http://www.zks.net/p3/how.asp
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