compiling a new kernel

**Tralfas** · 03-24-2008

ok this is my first time compiling the kernel since i installed gentoo. first i downloaded the new kernel source with this command ......

Code:

emerge gentoo-sources

now im having trouble getting to the next step in upgrading
(taken from this page TIP Upgrading your kernel - Gentoo Linux Wiki)

Code:

cp <old-source>/.config linux/.config

my question is how do i find out what the old source was so i can make the old config file part of the new source that way i dont have to go back through and redo the kernel?

**i92guboj** · 03-24-2008

Originally Posted by Tralfas

ok this is my first time compiling the kernel since i installed gentoo. first i downloaded the new kernel source with this command ......

Code:

emerge gentoo-sources

now im having trouble getting to the next step in upgrading
(taken from this page TIP Upgrading your kernel - Gentoo Linux Wiki)

Code:

cp <old-source>/.config linux/.config

my question is how do i find out what the old source was so i can make the old config file part of the new source that way i dont have to go back through and redo the kernel?

In Gentoo, when you emerge a kernel it sits into /usr/src/, under that directory you will have many subdirectories with the different kernel sources that you installed.

You can cd into that dir, and then use ls to see the installed kernel trees. Then use uname -r to see what version you are currently using. Whith the info from this two commands, you should be able to find which is the right thing to do.

I leave that as an exercise. If you can't find the way yourself, just post the output of these two commands here, and I will try to help:

$ ls -l /usr/src/
$ uname -r

**andrew.walker** · 03-24-2008

Not necessarily the correct way to do it but I just copy
/usr/src/linux-{current kernel}/.config to /usr/src/linux-{name of new kernel}/.config
or you can just go into the new kernel and do
make menuconfig
and load the previous .config file that way.

eselect kernel list should highlight the current kernel version unless you have changed it with eselect kernel set and uname -r should tell you what kernel you are currently running.

**dxqcanada** · 03-24-2008

You can also copy the current running config to .config by:

Code:

# zcat /proc/config.gz > /usr/src/<kernel>/.config

... assuming that a config.gz file was created by the kernel.

Here are a couple of references:

Gentoo Wiki
Gentoo Handbook

**i92guboj** · 03-24-2008

Having options is always a good thing. But since it seems that right now, the problem is that he can't find the source tree on his filesystems, I think we should keep this simple for now. Having too much info when you can't even do the basic can be a bit overwhelming, in my humble opinion.

**Tralfas** · 03-26-2008

thanks for all the help
i used cp to copy the old config to the new kernel source
then i used make oldconfig and went through all the questions
i compiled the kernel and copied the bzImage to /boot
then i changed grub to include the new kernel name
everything works and loads up except i think i need to use module rebuild so that alsa a nvidia works, because as of now i dont have a desktop just cli.

**i92guboj** · 03-26-2008

Originally Posted by Tralfas

thanks for all the help
i used cp to copy the old config to the new kernel source
then i used make oldconfig and went through all the questions
i compiled the kernel and copied the bzImage to /boot
then i changed grub to include the new kernel name
everything works and loads up except i think i need to use module rebuild so that alsa a nvidia works, because as of now i dont have a desktop just cli.

The nvidia drivers (and any other drivers that's not part of the kernel itself) need to be re-emerged each time you install a new kernel. Make sure that /usr/src/linux is pointing to the right kernel, because most of these packages use that link to choose the kernel that they will link against.

There are automatic tools for this, such as module-rebuild or whatever it's called. I can't comment on them because I never used them (for no particular reason, just laziness :P ).

**Tralfas** · 03-26-2008

i just used symlink in my make file so that it points to the right kernel instead of updating the symbolic link.

**Tralfas** · 03-27-2008

module-rebuild is pretty nice!

just

Code:

emerge module-rebuild

you just populate the list of modules that you need to reinstall(i only had an nvidia one)

Code:

module-rebuild populate

then rebuild the modules

Code:

module-rebuild rebuild

pretty easy!

thanks for the help once again!

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