Quantal backported kernel in 12.04.2? What's going on there?

Question

I'm sure that I'm not the first and/or only one to notice that 12.04.2, released earlier this year, installs by default a backported 3.5 kernel from the Quantal (12.10) release.

I'm surprised to see this in an LTS version, so I was wondering what's the reason for this?

It's the first time I noticed it on an LTS release.

Also: is there a method to upgrade to that or will I have to select manually that package (linux-image-generic-lts-quantal)?

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Comparing two fully updated systems

Originally installed with 12.04.1 installation CD

$ lsb_release -d && dpkg -l|grep linux-image|grep ^ii
Description:    Ubuntu 12.04.2 LTS
ii  linux-image-3.2.0-39-generic         3.2.0-39.62                             Linux kernel image for version 3.2.0 on 64 bit x86 SMP
ii  linux-image-3.2.0-40-generic         3.2.0-40.64                             Linux kernel image for version 3.2.0 on 64 bit x86 SMP
ii  linux-image-generic                  3.2.0.40.48                             Generic Linux kernel image

Originally installed with 12.04.2 installation CD

$ lsb_release -d && dpkg -l|grep linux-image|grep ^ii
Description:    Ubuntu 12.04.2 LTS
ii  linux-image-3.5.0-23-generic      3.5.0-23.35~precise1         Linux kernel image for version 3.5.0 on 64 bit x86 SMP
ii  linux-image-3.5.0-27-generic      3.5.0-27.46~precise1         Linux kernel image for version 3.5.0 on 64 bit x86 SMP
ii  linux-image-generic-lts-quantal   3.5.0.27.34                  Generic Linux kernel image

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$ apt-cache show linux-image-generic-lts-quantal
Package: linux-image-generic-lts-quantal
Priority: optional
Section: metapackages
Installed-Size: 27
Maintainer: Ubuntu Kernel Team <[email protected]>
Architecture: amd64
Source: linux-meta-lts-quantal
Version: 3.5.0.27.34
Depends: linux-image-3.5.0-27-generic, linux-firmware
Filename: pool/main/l/linux-meta-lts-quantal/linux-image-generic-lts-quantal_3.5.0.27.34_amd64.deb
Size: 2520
MD5sum: c9ad82fa12aacbd14324283cb9344ea9
SHA1: a2f9a758f605c116865b7c7fa6971bf77364bf62
SHA256: 08133998d027b5af18e2e3374e0723b4cf22baab28850cc89ca327a34b3094df
Description-en: Generic Linux kernel image
 This package will always depend on the latest generic 12.10 kernel image
 available.
Description-md5: c7e4fbc023632f2e538ff93b600ef34c
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Origin: Ubuntu
Supported: 18m

Solution

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:

1. 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.
2. 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:

• Will Ubuntu point releases include a new Linux kernel?
• http://www.jorgecastro.org/2013/02/19/what-the-lts-enablement-stack-means-for-sysadmins/

Comments

[gertvdijk]

Please note that this Quantal kernel reaches end-of-life as soon as Quantal does. On 12.04.2: apt-cache show linux-image-generic-lts-quantal | grep ^Supported #outputs Supported: 18m This baffles me as this 1.5yr supported kernel is installed on an LTS 5yr supported system. As you mentioned that this will be supported until the next LTS... I don't see this.

[Eliah Kagan]

@gertvdijk Will Precise have a newer point release, with a newer supported backported kernel by then, perhaps?

[Jorge Castro]

Yeah, by then the raring kernel will be backported.

[gertvdijk]

@JorgeCastro Perhaps you should then mention to use the hwe packages instead of lts-quantal. Since apt-cache show linux-image-hwe-generic | grep ^Supported # shows "Supported: 5y" indeed. You'll just receive newer kernels by the time the Quantal one is unsupported. Thanks :)

[Jorge Castro]

The -hwe- stack will just upgrade your kernel stack every 6 months between now and 14.04; that's probably what most people don't want.