[linux-elitists] Dual bore - a question on diagnosis

Gary Sandine linux-elitists@laclinux.com
Wed Dec 20 11:56:04 PST 2006

On Wed, 2006-12-20 at 13:49 -0500, Greg Folkert wrote:
> Or are you saying that 1GB would be used initially, then at some point
> later the machine would magically (or non-magically) recognize the
> additional memory giving full value.
> I know that answer I'd like it to be.

No doubt.  Maybe this thread will help:


Here's how one person eliminated the behavior in a Centrino laptop
running 32 bit Ubuntu (and used all of his 1 gig of RAM).  There's no
link to this discussion because it's from a private Request Tracker
database.  It might give you something to go on -- it led me to the lkml
thread above:

<blockquote author="Karl Hegbloom">
This solution is for Debian or Ubuntu. The thing is that the script
needs to run as soon as possible, since the computer may be very slow
until after it has run. Place the following script
into /etc/mkinitrd/scripts/30-mtrr-lucgm:


mv $INITRDDIR/linuxrc $INITRDDIR/linuxrc.real

cat <<EOF > $INITRDDIR/linuxrc
if [ ! -f /proc/mtrr ]; then
mount -t proc proc /proc

echo "disable=5" >/proc/mtrr
echo "disable=4" >/proc/mtrr
echo "disable=3" >/proc/mtrr
echo "disable=2" >/proc/mtrr
echo "disable=1" >/proc/mtrr
echo "disable=0" >/proc/mtrr
echo "base=0x00000000 size=0x40000000 type=write-back" >/proc/mtrr

if [ -n "$mttr_MOUNTED_PROC" ]; then
umount /proc


cat $INITRDDIR/linuxrc.real >> $INITRDDIR/linuxrc
rm $INITRDDIR/linuxrc.real

chmod +x $INITRDDIR/linuxrc


Then, re-create the initrd with:

mkinitrd -o /boot/initrd.img-$(uname -r) /lib/modules/$(uname -r)

Edit the /boot/grub/menu.lst and remove the 'mem=' from kopts, run
'update-grub', and reboot. You'll now have all the RAM and a fast

More information about the linux-elitists mailing list