Upgrading the Kernel

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Revision as of 08:29, 12 September 2008 by Demus (Talk | contribs)

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Introduction

The ability to change kernel versions at will can be extremely useful for fighting driver bugs and regressions. The kernel version that ships with LinuxMCE 0710 is 2.6.22-14. At the time of writing the most recent kernel version is 2.6.26.5. The .22 kernel is almost a full year old and as such does not support a lot of the newer hardware.

Caveats

Some modules that are part of the vanilla Linux MCE installation are not part of the standard Linux kernel. These modules have been added as part of the Ubuntu distribution or by LMCE. It is not always straight forward, or even possible to compile these modules against different kernel sources. I suggest you read this entire Wiki first, to determine if you will be affected by the missing modules.

Alternatives

Usually kernels are upgraded for better driver support. In these cases it is often easier to compile new versions of modules against the 2.6.22-14 kernel than it is to upgrade the whole kernel (for reasons mentioned in the caveats section. Unfortunately, a lot of modules depend on other modules or patches in the kernel. So this option is not always possible.

Example: 

cd ~
wget http://www.somesite.com/some_kernel_driver.c
echo obj-m = some_kernel_driver.o > Makefile
cd /lib/modules/2.6.22-14-generic/build
make M=~ modules
ls -l ~/some_kernel_driver.ko

You may then copy the module to the appropriate directory in the modules tree.

Upgrade process

This wiki will provide step-by-step instructions on how to upgrade your kernel. These examples will assume you are upgrading to 2.6.26 from 2.6.22. You may however apply these steps to any 2.6 kernel.

Potential problems

All the normal issues of upgrading your kernel apply. Always keep your old, working kernel on hand.

Steps

The first step is to grab the kernel source and extract it to the /usr/src folder. 

wget http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.26.5.tar.bz2
tar -jxvf linux-2.6.26.5.tar.bz
rm linux
ln -s linux-2.6.26.5 linux

Now lets copy the .config file from our generic 2.6.22 kernel. 

cd linux
cp /boot/config-2.6.22-14-generic .config

On our first load of menuconfig there will be many warnings displayed about non-existant config options. This is simply due to the removal or renaming of old options. Most of these warnings are insignificant, and enabled by default in the vanilla kernel. I would quickly go over the list of warnings and verify that any drivers you need haven't been renamed. One option that has been renamed is DVB_CORE_ATTACH. It is now DVB_MEDIA_ATTACH, and you may need it if you use the DVB stack. Also some netfilter matches have been renamed. Simply reselect these from the config menus. You may also need to install the ncurses library and development files if you haven't already. 

apt-get install libncurses5 libncurses5-dev
make menuconfig 2> module_errors

It's also a good idea to go over the kernel and make any optimizations for your particular system. The performance gain from these options is fairly minor, but definitely worth selecting.

I opted to change these things:

  • Selected exact processor family to enable processor optimization extensions
  • Selected preemptive kernel (low latency)
  • Build SATA driver into kernel
  • Build MD,RAID1,RAID5 modules into kernel
  • Build NIC module into kernel
  • Disabled kernel debugging (Note: This is very important if you plan to use this kernel on Media Directors.)


At this point you can start the kernel build process. You may use the standard kernel method or the Debian build method. For simplicity this Wiki will use the standard method. 

make
make modules_install

You should now build any custom modules you need. Linux MCE (and Ubuntu) come with some non-standard drivers. The key modules to worry about are AppArmor, Asterisk (ztdummy & zaptel), ALSA, nVidia video, ATI video. You are better off downloading the latest nVidia and ATI drivers and installing them using the instructions found in the display drivers wiki. The Gutsy kernel also contains other important video drivers, like ivtv. However most of these drivers are now in the mainstream kernel and more up-to-date than the Gutsy versions.

I have decided to forgo the AppArmor module. Compiling and running this module would require a complete upgrade of the whole package in addition to manually patching many areas of the kernel. This is entirely too much work for something that is largely useless in a Linux MCE installation.

For the ALSA drivers I opted to upgrade the whole package. The compilation and installation is so straight forward that there's no reason to play around with mixmatched versions. Just rebuild both the kernel drivers and the userspace utilities. Here are the steps for that (Note: You should select your card specifically for the alsa-driver package, using the --with-cards option): 

mkdir alsa
cd alsa
wget ftp://ftp.alsa-project.org/pub/driver/alsa-driver-1.0.17.tar.bz2
wget ftp://ftp.alsa-project.org/pub/firmware/alsa-firmware-1.0.17.tar.bz2
wget ftp://ftp.alsa-project.org/pub/lib/alsa-lib-1.0.17a.tar.bz2
wget ftp://ftp.alsa-project.org/pub/plugins/alsa-plugins-1.0.17.tar.bz2
wget ftp://ftp.alsa-project.org/pub/utils/alsa-utils-1.0.17.tar.bz2
wget ftp://ftp.alsa-project.org/pub/oss-lib/alsa-oss-1.0.17.tar.bz2
for fi in *; do
tar -jxvf $fi
done
cd alsa-driver-1.0.17 
./configure --with-cards=hda-intel
make
make install
cd ..
for fi in alsa-lib-1.0.17a alsa-plugins-1.0.17 alsa-utils-1.0.17 alsa-oss-1.0.17 alsa-firmware-1.0.17; do
cd $fi
./configure
make
make install
cd ..
done

For Asterisk, simply download the latest Zaptel sources. Configure, Make, Install. 

wget http://downloads.digium.com/pub/zaptel/zaptel-1.4.12.1.tar.gz
tar -zxvf zaptel-1.4.12.1.tar.gz
cd zaptel-1.4.12.1
./configure --prefix=/usr
make
make install

You will also need to recompile LIRC. Note: Some LIRC drivers are not SMP safe and will not compile on SMP kernels. In this case I suggest you pick only the drivers you need. For 2.6.26.5 I had to patch some files in the kernel to get LIRC to compile. The patch is located on the LIRC site. Also only the CVS version will compile. I ran into even more drama with LIRC, because many drivers failed to even attempt a build. I was able to manually enter each driver directory and perform a make/make install. After applying the patch to the kernel, it failed to compile as well. At this point I would assume that LIRC is not working with 2.6.26.5. 

cd /usr/src/linux
wget http://lirc.sourceforge.net/software/snapshots/lirc-bttv-linux-2.6.24.patch
patch -p1 < lirc-bttv-linux-2.6.24.patch
cd ..
cvs -z8 -d:pserver:anonymous@lirc.cvs.sourceforge.net:/cvsroot/lirc co lirc
cd lirc-0.8.3
./configure --prefix=/usr --with-driver=all
make
make install

Copy your kernel image to your /boot folder. Create a new initramfs image. Update your menu.lst file. 

cp arch/yyxx/boot/bzImage /boot/vmlinuz-2.6.26.5
mkinitramfs -o /boot/initrd.img-2.6.26.5 2.6.26.5
nano /boot/grub/menu.lst

Save a list of all currently used modules for future reference. You will use this later to make sure you have all the required modules. 

lsmod > ~/module_list-2.6.22.14

Go ahead and reboot. Your new kernel should now load. If your boot fails, simply edit the parameters from the grub menu and specify your old kernel and initramfs image. Please note: udev attempts to assign persistent names to most devices. If the way the kernel identifies your device changes from your old kernel version to the new one, udev may assume it's a new device and assign it an unexpected name. For example, the nForce ethernet drivers corrected a bug in the way the MAC address was read from the device. On my first boot what was usually my eth0 device was now my eth1 device. To fix this simply flush the offending rule from the /etc/udev/rules.d folder. 

reboot

You will most likely need to reinstall your video driver at this point, if you used a proprietary binary version. Instructions for getting the latest driver and installing it can be found in the display drivers wiki.

For nVidia do this: 

wget http://us.download.nvidia.com/XFree86/Linux-x86_64/173.14.12/NVIDIA-Linux-x86_64-173.14.12-pkg2.run
sh NVIDIA-Linux-x86_64-173.14.12-pkg2.run

Now it is a good idea to compare your lsmod output from your old kernel to the output of your new kernel. Just to be certain you didn't miss anything. I found the order to be different, so I copied the output to an Excel spreadsheet and sorted the two different lists. The only discrepancies I found were related to name changes in the kernel and AppArmor.

Media Directors

In a traditional installation the Core and Media Directors all run the Gutsy 2.6.22-14 kernel. You may still use this kernel if you like, or you may opt to use your newly built kernel.

Use old kernel

If you want the media directors to continue to use this old kernel then you must create a symlink to the old kernel in the boot directory of each MD. You must also update the MD archives with this symlink, so it future MDs will be setup correctly. 

mkdir /tmp/moonfs_64 /tmp/moonfs_32
tar -jxvf /usr/pluto/install/PlutMD-adm64.tar.bz2 /tmp/moonfs_64/
tar -jxvf /usr/pluto/install/PlutMD-i386.tar.bz2 /tmp/moonfs_32/
for md in /usr/pluto/diskless/* /tmp/moonfs_64 /tmp/moonfs_32; do
md_device=`echo "$md" | sed -e 's/.*[/]\([^/]\)/\1/g'`
cd $md/boot
ln -s vmlinuz-2.6.22-14-generic vmlinuz-2.6.26.5
ln -s initrd.img-2.6.22-14-generic initrd.img-2.6.26.5
done
tar -C /tmp/moonfs_64 -jcvpf /usr/pluto/install/PlutoMD-adm64.tar.bz2 .
tar -C /tmp/moonfs_32 -jcvpf /usr/pluto/install/PlutoMD-i386.tar.bz2 .
rm -rf /tmp/moonfs_*

Use new kernel

A better route, although more complex one is to use your new kernel on the media directors as well. You can do this by copying your kernel and modules to each MD root filesystem. Additionally, you will need to add the kernel image plus modules to the MD root archive (/usr/pluto/install/PlutoMD-xxxyyy.tar.bz2) where xxxyyy is your architecture. This does present an issue if your core and media directors are not the same architecture. In this case you will need to build a kernel for the other architecture using cross-compile methods or using a machine of the that architecture.

Warning: Make sure your initramfs file is around 10MB. If you have kernel debugging enabled the file will be too large to transfer over tftp and net boots will fail.

Note: These scripts assume all media directors and cores are the same architecture. You should manually copy the files if you use a mixture of i386 and amd64 machines. 

for md in /usr/pluto/diskless/*; do
md_device=`echo "$md" | sed -e 's/.*[/]\([^/]\)/\1/g'`
cp /boot/vmlinuz-2.6.26.5 $md/boot/
cp /boot/initrd.img-2.6.26.5 $md/boot/
cp /lib/modules/2.6.26.5/ $md/lib/modules/
/usr/pluto/bin/Diskless_InstallKernel.sh $md_device
done
/usr/pluto/bin/Diskless_BuildDefaultImage.sh


Now rebuild the archives, so future Media Directors will get the correct kernel image. 

cd /tmp
mkdir moonfs_amd64
cd moonfs_amd64
tar -jxvf /usr/pluto/install/PlutMD-adm64.tar.bz2
cp /boot/vmlinuz-2.6.26.5 boot
cp /boot/initrd.img-2.6.26.5 boot
tar -jcvpf /usr/pluto/install/PlutoMD-adm64.tar.bz2 *
cd ..
rm -rf moonfs_amd64
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