+----------------------+
| Kernel Compile Notes | c  o  m  p  u  t  e  r  g  l  i  t  c  h
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These notes are not meant as guides at all, they are simply notes I have taken after 
fighting with some kernel compiles. Use them at your own risk.

Compiling High Memory Support into a Debian 2.6.8 Kernel.

The running kernel was: 2.6.8-2-386 When I upgraded the RAM in the server from 
512Mb to 2Gb Debian was reporting it had only 1Gb

To fix this problem High Memory Support had to be enabled in the kernel configuration.

I was having some problems with apt and didn't have the time to go about fixing it at the 
time so I downloaded the following packages from the Debian website:

bzip2_1.0.2-7_i386.deb
fakeroot_1.2.10_i386.deb
initrd-tools_0.1.81.1_i386.deb
kernel-package_8.135_all.deb
libncurses5-dev_5.4-4_i386.deb

Install all the packages:
dpkg -i bzip2_1.0.2-7_i386.deb 
etc


I then downloaded kernel-source-2.6.8_2.6.8.orig.tar.gz to /usr/src and extracted it:
tar xvzf kernel-source-2.6.8_2.6.8.orig.tar.gz
mv kernel-source-2.6.8_2.6.8 kernel-source-2.6.8-2.6.8-highmem

Then changed to the kernel source directory and begin the configuration process:
cd kernel-source-2.6.8-2.6.8-highmem
make menuconfig

First thing was to Load an Alternate Configuration File which was the kernel currently 
running located at /boot/config-2.6.8-2-386 (this is to keep the current working 
configurations from the old kernel added to the new kernel)
Now to add High Memory Support:
Processor type and features  ---> High Memory Support (4GB)  ---> (X) 4GB
Exit and save the changes

Now its time to compile the kernel:
# cd /usr/src/kernel-source-2.6.8-2.6.8-highmem
# make dep
# make-kpkg clean
# fakeroot make-kpkg --revision=Custom.1.0 --initrd --append-to-version=-highmem 
kernel_image

I was getting the following error:
make[3]: *** No rule to make target `drivers/net/tg3.c', needed by `drivers/net/tg3.o'.  
Stop.

After some research it turned out it was a driver for the:
Ethernet (1000 Mbit) ---> <M> Broadcom Tigon3

I went back to make menuconfig and disabled the module and everything went smoothly.
Next it was time to install the new kernel:

# cd /usr/src
# dpkg -i kernel-image-2.6.8-highmem_Custom.1.0_i386.deb

Check /boot/ and /boot/grub/menu.1st and make sure everything's in order, reboot into 
the new kernel and check the memory reading:
# free
             total       used       free     shared    buffers     cached
Mem:       2596672    1273024    1323648          0     144784     371028
-/+ buffers/cache:     757212    1839460
Swap:       747012          0     747012

Success!