Messages in this thread | | | Date | Mon, 4 Jun 2007 17:54:46 -0700 | From | "Yinghai Lu" <> | Subject | Re: Intel's response Linux/MTRR/8GB Memory Support / Why doesn't the kernel realize the BIOS has problems and re-map appropriately? |
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On 6/4/07, Andi Kleen <andi@firstfloor.org> wrote: > > From their e-mail: > > > > Note before continuing: Debian* Linux Operating System is not an > > officially, validated, tested Operating System for the Intel(R) Desktop > > Board DG965WH > > (see http://downloadcenter.intel.com/Product_Filter.aspx?ProductID=2375); > > moreover, we do confirm that "on a system that has 8 GB of system memory > > installed, it is not possible to use all of the installed memory due to > > system address space being allocated for other system critical functions." > > [qtd. on page 43 of the Technical Product Specification (see > > http://download.intel.com/design/motherbd/wh/D5600801US.pdf)]. Thus, the > > following suggestions are provided AS IS; we cannot guarantee the problem > > would be fixed afterwards: > > They're talking about something different than your issue. If you put in > the fully possible 8GB (4x2GB) then some memory will be lost to the PCI hole > because the desktop ICH can only access 35bits (8GB) in hardware. > > That can be up to 2GB in extreme cases, usually <0.5-1GB depending > on how much mapping space your hardware needs. > > But if you put in less than 8GB the BIOS is supposed to remap > the memory around the PCI hole and set up the MTRRs correctly > so that the PCI hole is uncached and the memory around it is cached. > > That is 100% the BIOS' responsibility and if it doesn't do that > it is buggy.
then the BIOS need to disable mem remap to make thing simple if there 8G ram installed.
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