Messages in this thread | | | Date | Thu, 31 May 2007 08:27:27 -0600 | From | Robert Hancock <> | Subject | Re: Case: 7454422: Re: Kernel 2.6.21.3 does not work with 8GB of RAM on Intel 965WH motherboards. (FULL DMESG) |
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Justin Piszcz wrote: > On Thu, 31 May 2007, Parag Warudkar wrote: > >> Robert Hancock wrote: >>> I think that mem=8832M would work as well, to make the kernel use >>> only the memory that is marked cacheable. (It looks like this >>> parameter takes the highest memory address we want the kernel to use, >>> not the highest memory amount.) >>> >> Yep, and that would be much easier too. >> >> I am curious though as this seems to be somewhat common a problem, >> could we make the kernel analyze which memory is not cacheable (it >> already knows this via MTRR) and not use that portion for anything? >> Plus may be warn the user to contact their BIOS vendor to correct the >> problem? >> >> I think that would be possible - even if the kernel knows late that >> the memory was uncached we could migrate those pages in that region to >> someplace else? >> >> Parag >> > > That is an excellent question and I wonder the same thing. I also had > this problem when I only used 4GB of ram and upgraded the (another > motherboard, I have two) past version 1666P and I had no idea what was > going on other than the BIOS did not work correctly. > > In this case however it worked with 4GB with bios version 1612P but not > with 8GB. Is this the case of a buggy BIOS for the 965 chipset or do > Intel boards have a lot of issues?
We could conceivably generate a warning if the MTRRs don't map all of the physical memory as write-back. Actually, conceivably we could actually go and fix up the MTRRs if we found them to be wrong according to the E820 memory map. That would be more complicated, however.
-- Robert Hancock Saskatoon, SK, Canada To email, remove "nospam" from hancockr@nospamshaw.ca Home Page: http://www.roberthancock.com/
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