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I have two Dell laptops:

  1. Laptop A ( Dell laptop ) which was upgraded to 20.04.3 LTS a year or so ago from 18.04.x LTS. This has:
Linux 5.4.0-96-generic #109-Ubuntu SMP Wed Jan 12 16:49:16 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
  1. Laptop B, a new Dell laptop which had Windows11 and wiped it out with Ubuntu 20.04.3 LTS installed from a live USB. During the install, I selected the option to upgrade automatically from the repositories. This new latop have the following kernel :
Linux 5.13.0-27-generic #29~20.04.1-Ubuntu SMP Fri Jan 14 00:32:30 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux

Both of the above laptops have :

$ cat /etc/lsb-release 
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=20.04
DISTRIB_CODENAME=focal
DISTRIB_DESCRIPTION="Ubuntu 20.04.3 LTS"

Both also have livepatch enabled.

The question is: What am I missing that as to why does laptop A ( in item [1] ) never upgrades the kernel to 5.13.x like what laptop B have when laptop B is freshly installed ?

I literally type:

sudo apt-get update
sudo apt-get upgrade

... everyday on laptop A. Although it upgrades to the latest 5.4.x kernel ... never upgrades to 5.13.x kernel.

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1 Answer 1

6

Ubuntu LTS releases have two main kernel stack choices

GA or the general kernel stack

This kernel stack remains the same for the life of the product. For Ubuntu 20.04 LTS it will use the 5.4 kernel.

HWE or hardware enablment stack

This kernel stack will change as the release advances.

At

  • 20.04.2 it uses the 5.8 kernel stack from Ubuntu 20.10
  • 20.04.3 it uses the 5.11 kernel stack from Ubuntu 21.04
  • 20.04.4 it uses the 5.13 kernel stack from Ubuntu 21.10 (20.04 or focal is progressing to 20.04.4 currently with some of the packages already installed)
  • 20.04.5 will use the 5.15 kernel stack from Ubuntu 22.04 LTS (the GA stack for 22.04).

See https://wiki.ubuntu.com/Kernel/LTSEnablementStack for details.

Ubuntu Server installs default to the more stable GA stack, but it can be changed at install, and post-install.

Ubuntu Desktop installs default to the HWE stack by default, but can be changed post-install.

Ubuntu flavors can vary depending on media; I'll use Lubuntu 20.04 as example.

  • Lubuntu 20.04 & 20.04.1 media defaults to GA kernel stack for new installs
  • Lubuntu 20.04.2 & later media defaults to HWE kernel stack for new installs.

Other OEM kernel stacks can also be used for new installs; if the installer detects your hardware as benefiting from an OEM kernel.

You can have both kernel stacks (GA & HWE) installed on a system as well; meaning you'll have more to upgrade (both will get updates), but the bandwidth & disk space used isn't that great; you select at boot (ie. grub) which you'll use. However do note some closed-source or proprietary video drivers do not allow both stacks to co-exist.

Refer to the provided wiki page how to install/switch installs; eg. to switch from HWE to GA (for Ubuntu Desktop 20.04 LTS) search for "To downgrade from HWE/OEM to GA kernel:"

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  • Maybe also add how to replace the GA stack with the HWE stack. Jan 23 at 5:57
  • It's covered in the wiki I provided... Yeah this site does like being a 'goto' for howto's... but I'd prefer to point to the official doc instead (ie. when changes are made; official docs are changed; sites like this tend to trail & become dated.. thus my preference to point where to find the info officially). @ArchismanPanigrahi
    – guiverc
    Jan 23 at 6:01
  • Thanks! So I managed to install the HWE stack during install from live USB without even realising it. I do recall selecting the option to install any proprietary drivers, which ended up using creating a MOK signature for SecureBoot ad this new laptop B has an nVidia discrete GPU while laptop A has an AMD Radeon discrete GPU. Although this new install on laptop B simply seems to have used the nouveau drivers instead.
    – jmsjr
    Jan 23 at 6:13
  • I now have the older laptop ( laptop A ) now also use HWE stack ( 5.13.0-27 ) with Ubuntu 20.04.3 LTS. Thanks all !
    – jmsjr
    Jan 23 at 6:28
  • I'm on Ubuntu 20.04.4 LTS, and have had to boot into 5.11.0-43-generic because 5.13.0-27-generic and 5.13.0-28-generic gave me issues and are missing from when I boot entries. How can I get into 28?
    – chx101
    Jun 9 at 10:04

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