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I have a laptop with 4GB of RAM but only 3GB are seen by my linux system. I'm currently using linux-2.6.29.1 I read somewhere that you could fix this even ...
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  1. #1
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    kernel support for PAE


    I have a laptop with 4GB of RAM but only 3GB are seen by
    my linux system. I'm currently using linux-2.6.29.1
    I read somewhere that you could fix this even with 32-bit addressing
    by setting CONFIG_X86_PAE while building the kernel

    I ran
    # grep 'PAE' /boot/config-2.6.29.1
    and
    # grep 'CONFIG_X86_' /boot/config-2.6.29.1

    and none of these returned a string with PAE on it

    Has it been renamed to something else? Or is it somewhere else?

  2. #2
    Linux Engineer b2bwild's Avatar
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    The Linux kernel includes full PAE support starting with version 2.6,enabling access of up to 64 GB of memory on 32-bit machines. A PAE-enabled Linux-kernel requires that the CPU also support PAE

    I guess you should check settings in BIOS, check how much memory your Graphics card take. well, that wont be 1GB for sure.
    Never make any misteaks.

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  3. #3
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    I got this figured out

    yesterday I built latest kernel (2.6.29.2) and this time in
    make menuconfig
    instead of checking 'up to 4GB' I checked the '64GB'
    After building and rebooting the 'free' command this time
    displayed the correct total amount of RAM (4GB)

    Some excerpts from my config

    # Linux kernel version: 2.6.29.2
    #
    # CONFIG_64BIT is not set
    CONFIG_X86_32=y
    # CONFIG_X86_64 is not set
    CONFIG_X86=y
    CONFIG_ARCH_DEFCONFIG="arch/x86/configs/i386_defconfig"
    #
    CONFIG_MCORE2=y
    # CONFIG_GENERIC_CPU is not set
    CONFIG_X86_GENERIC=y
    CONFIG_X86_CPU=y
    ...
    #
    CONFIG_X86_CMPXCHG64=y
    ...
    # CONFIG_NOHIGHMEM is not set
    # CONFIG_HIGHMEM4G is not set
    CONFIG_HIGHMEM64G=y
    CONFIG_PAGE_OFFSET=0xC0000000
    CONFIG_HIGHMEM=y
    CONFIG_X86_PAE=y
    CONFIG_ARCH_PHYS_ADDR_T_64BIT=y
    ...
    CONFIG_PHYS_ADDR_T_64BIT=y

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