Messages in this thread | | | Date | Thu, 07 Jun 2007 09:33:52 -0400 | From | Tom Moore <> | Subject | Re: 4Gb ram not showing up |
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Satyam Sharma wrote: > On 6/6/07, Lennart Sorensen <lsorense@csclub.uwaterloo.ca> wrote: >> [...] >> A better description would be: >> >> "Select this if you have a 32-bit processor and memory mapped in the 1GB >> to 4GB address range." >> [...] >> That one would be better as: >> >> "Select this if you have a 32-bit processor and ram mapped in the >> address >> range above 4GB." > > Ugh, no! How can we expect the user compiling a kernel to be *so* > familiar with address space re-mapping / BIOSen (_his_ particular > BIOS, specifically, and what / how it re-maps memory) / etc to be > able to answer such questions? "Select ... if you have ... RAM > installed" is perfectly clear, simple, and all that's needed. > However the KConfig help message as it is currently written is wrong. > BTW, just imagine what a user would need to do to make things > work as per your proposal. Build some kernel (don't care about > memory loss), boot and find what his firmware prefers to do with > address space (or else read up the BIOS documentation!) and > _then_ again build a new kernel, this time selecting the options > appropriately ... I tried to do this, but the Kconfig help message was misleading. I still needed to come here for help. > > Also, note that the change you're proposing is unnecessary! As > Andi pointed out, this issue has more to do with broken BIOSen > and the proper fix for Tom is to contact his vendor and flash / > upgrade the BIOS firmware. I don't see anything wrong with the > Kconfig help texts. Andi was wrong. It appears that he read the first sentence of my email and jumped to a conclusion. The /proc/mtrr output that I included in my first post showed the my bios was doing the right thing. My problem was that I was using CONFIG_HIGHMEM4G, which is what the KConfig help message told me to do. After switching to CONFIG_HIGHMEM64G the OS was able to map all of my ram.
total used free shared buffers cached Mem: 4016768 3924312 92456 0 360132 3030336 -/+ buffers/cache: 533844 3482924 Swap: 5116692 2676 5114016
Thanks to those with the correct advice. I'm sure I would have got this by trying each memory model in turn, but at least now I know what is going on.
Tom
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