Ubuntu – have different kernel versions on same distribution version

12.04kernelltsmythbuntuupgrade

I (re)installed Mythbuntu 12.04.2 to solve an audio problem. After the installation I find that the kernel version of this MythTV front-end is 3.5.0-27-generic.

However on the fully-updated Mytbuntu 12.04… Front-end/Back-end server (Installed as 12.04.1), the kernel version is 3.2.0-40-generic.

Why are these different version, I wonder…

Best Answer

This is explained in the release notes for Precise:

By default, the 12.04.2 point release will ship with a newer 3.5.0-23.35 Ubuntu kernel from Quantal, and a matching X.org stack. This is based on the 3.5.7.2 Extended Upstream Stable Kernel Release...The purpose of providing a newer kernel in the 12.04.2 point release is for hardware enablement.

This only applies to Ubuntu, Edubuntu, and Mythbuntu.

In short, you get the newer kernel if you install from 12.04.02; but keep the older kernel if you update 12.04.01, unless you take steps to enable the update.

For more information on how to do that and various policies and procedures on this issue, see LTS Enablement Stacks.

From the above link:

Anyone wishing to opt into the hardware enablement stack for Precise may do so by installing the linux-generic-lts- and xserver-xorg-lts- packages.

For example to install the Quantal hardware enablement packages in Precise, please run the following command:
sudo apt-get install --install-recommends linux-generic-lts-quantal xserver-xorg-lts-quantal
libgl1-mesa-glx-lts-quantal

To install the Raring hardware enablement packages in Precise, please run instead the following command:
sudo apt-get install --install-recommends linux-generic-lts-raring xserver-xorg-lts-raring libgl1-mesa-glx-lts-raring

See the above link for additional specifics regarding the exact policies and procedures regarding the support, maintenance, and upgrade paths for these hardware enablement stacks.

The support schedule for the kernels is given at the Version Matrix

Related Solutions

12.04 Kernel LTS – How to Remove Kernel/LTS Enablement Stack

Important: The below instructions only work if you have one of the pre-enablement stack kernels installed still, e.g. 3.2.0-38.

With the Enablement Stack installed run 'uname -r' to check the current kernel version. Substitute it into the command below:

sudo apt-get purge linux-generic-lts-quantal xserver-xorg-lts-quantal linux-headers-generic-lts-quantal linux-image-generic-lts-quantal linux-image-3.5.0-25-generic linux-headers-3.5.0-25

Re-install important components (including X itself!) that are removed due to dependencies by the above commands:

sudo apt-get install xserver-xorg xserver-xorg-input-synaptics

Fix the steam client:

sudo apt-get install libgl1-mesa-glx:i386

Finally, reboot your computer.

IMHO the enablement stack isn't ready for release. In my experience Virtualbox, Samba, and the Steam client all break with the Enablement Stack installed. There's a workaround for Virtualbox but none for Samba or Steam so far (March 2013).

Quantal Backported Kernel in 12.04.2 – Explanation

The 12.04.2 and later release ISOs have a Hardware Enablement Stack to allow 12.04 to run on newer hardware.

https://wiki.ubuntu.com/Kernel/LTSEnablementStack

In an effort to support a wider variety of hardware on an existing LTS release, the 12.04.2 and newer point releases will ship with an updated kernel and X stack by default. These newer hardware enablement stacks will be comprised of the newer kernel and X stacks from Quantal, Raring, and Saucy.

To optionally install it manually (if you've installed from earlier 12.04 release images):

sudo apt-get install --install-recommends \
     linux-generic-lts-quantal \
     xserver-xorg-lts-quantal \
     libgl1-mesa-glx-lts-quantal

and leave out the last two lines for servers (usually no graphics installed).

Here's how support will work for the stacks:

If your hardware is supported by 12.04.1, you can install the 12.04.1 it will be supported until 2017 with no extra effort on your part.
If you install from a later point release (due to requirements for newer hardware support, or for other reasons), your hardware stack will be upgraded in 2014 (approximately June) to the 14.04 hardware enablement stack. The 14.04 enablement stack will then be supported on 12.04 installs until the 12.04 end of life, in April 2017.

If you want to remove it:

How to remove Kernel/LTS Enablement Stack?

More info:

Best Answer

Related Solutions

12.04 Kernel LTS – How to Remove Kernel/LTS Enablement Stack

Quantal Backported Kernel in 12.04.2 – Explanation

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