Arch Linux

cherio

Member

Registered: 2022-04-27

Posts: 34

New LTS kernel is the same version as the mainsteam - no safety net

I have always assumed that having an LTS kernel provides a safe alternative boot when the mainline kernel version is causing an issue.
Now that LTS version is the same, there is no plan B in case the mainline kernel directly or indirectly is causing problems.

Like many ordinary users (who are a majority) I am terrified of compiling and installing my own kernel.
The wiki article about kernel mentions that previous LTS kernel versions are maintained in AUR, however 5.15 is not there (yet).

I still have 5.15 kernel packages cached

$> cd /var/cache/pacman/pkg; ls | grep ls | grep linux-lts-5.15
linux-lts-5.15.94-1-x86_64.pkg.tar.zst
linux-lts-5.15.94-1-x86_64.pkg.tar.zst.sig

would it be safe to simply downgrade kernel from there, e.g.?

$> pacman -U /var/cache/pacman/pkg/linux-lts-5.15.94-1-x86_64.pkg.tar.zst

I am not sure if replacing LTS kernel this way will bring the necessary dependencies, update the grub entry, etc

What could be a reasonably simple fallback option at this time?

loqs

Member

Registered: 2014-03-06

Posts: 18,962

Re: New LTS kernel is the same version as the mainsteam - no safety net

$> pacman -U /var/cache/pacman/pkg/linux-lts-5.15.94-1-x86_64.pkg.tar.zst

I am not sure if replacing LTS kernel this way will bring the necessary dependencies,

If you need linux-lts-headers or any of acpi_call-lts nvidia-lts r8168-lt tp_smapi-lts you need to add those to the list to be downgraded from the cache.

update the grub entry, etc

No difference in this respect to if it was installed from the repositories.

cherio

Member

Registered: 2022-04-27

Posts: 34

Re: New LTS kernel is the same version as the mainsteam - no safety net

If you need linux-lts-headers or any of acpi_call-lts nvidia-lts r8168-lt tp_smapi-lts you need to add those to the list to be downgraded from the cache.

This is helpful.

Coincidentally (or maybe not) just this morning linux-lts515 package popped up in AUR.

michael8rown

Member

Registered: 2021-08-25

Posts: 27

Re: New LTS kernel is the same version as the mainsteam - no safety net

What could be a reasonably simple fallback option at this time?

I don't think this qualifies as a "simple fallback option", but I personally have been looking into option 3.2 of the Arch Linux Archive because I've been having quite a few brand new problems lately on an Arch system I've been running without incident for over a year now. My problems seem to be related to kernel 6.1. I was doing fine until the LTS moved to 6.1, too. That link explains how to roll back your entire installation to a specific date (I don't think it's possible--or at least not advisable--to roll back the kernel by itself while everything else remains updated). The biggest problem for me in using the archive is that I would be stuck at that point in time without any updates at all.

I've never been bitten by an update like this, and it's been pretty frustrating.

Last edited by michael8rown (2023-02-24 17:53:06)

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 25,255

Re: New LTS kernel is the same version as the mainsteam - no safety net

The kernel is one of the few packages where it is relatively safe to stay on an older release while the rest of the system rolls on. Regarding the issues you are experiencing is that by using the LTS kernel you essentially freeze your kernel level support to a year old baseline (security and bugfixes nonwithstanding). so the change to a new LTS will always be quite disruptive. Note that some of the "common" pitfalls here are some changes in the kernel that have an effect on nvidia handling, so if you are using nvidia, make sure you've seen  https://wiki.archlinux.org/title/NVIDIA#Installation the blue boxes and https://wiki.archlinux.org/title/NVIDIA … grated_GPU if you have an integrated GPU active that you are not actively utilizing for anything.

seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 76,378

Re: New LTS kernel is the same version as the mainsteam - no safety net

I've been having quite a few brand new problems lately on an Arch system I've been running without incident for over a year now. My problems seem to be related to kernel 6.1 … I've never been bitten by an update like this, and it's been pretty frustrating.

It might be helpful to indicate what "problems" are.
https://bbs.archlinux.org/viewtopic.php?id=57855

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