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226

I understand that HWE kernels arrive few months after non-LTS release comes out. Is there a chance to make it instantly available for LTS users with HWE-edge branch?

227

Not really, no. Thereā€™s no such thing as an optional kernel. Itā€™s either in the archive (and thus fully supported) or itā€™s not. The bar to get a kernel into the archive sits fairly high, so we canā€™t and donā€™t want to do that for short-lived kernels. All DKMS packages from the archive need to compile, all autopkgtests need to pass, the AppArmor patchset needs to be updated and functional, ā€¦ and probably other things that Iā€™m not aware of.

What youā€™re looking for is a rolling kernel which is not feasible at the moment.

But nothing prevents you from using mainline builds [1] or packages from any of our build [2], bootstrap [3] or unstable [3] PPAs. Just be aware that none of this is supported nor fully tested nor patched for security or other issues on an on-going basis.

[1] Ubuntu Mainline Build Status
[2] https://launchpad.net/~canonical-kernel-team/+archive/ubuntu/ppa
[3] https://launchpad.net/~canonical-kernel-team/+archive/ubuntu/bootstrap
[4] https://launchpad.net/~canonical-kernel-team/+archive/ubuntu/unstable

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228

Iā€™m afraid not. For the same reasons mentioned in my previous comment.

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229

So, if a regular user experiences an issue because his hardware is very new, what would be the solution thatā€™d be supported by Canonical (all unsupported solutions are out of the window)?

230

You would have to wait for the next interim release which would have the latest upstream kernel, and if you are on an LTS you would then need to wait a bit longer for it to roll as an HWE.

231

Hello Kernel Team, please enable ā€œSamsung Galaxy Book driverā€ in the next kernel.
Thank you

232

Hi @sandra0815. A notebook device like the Samsung Galaxy Book requires several kernel device drivers in order for it to work properly with Linux. The Ubuntu kernel inherits most of those drivers from the upstream Linux kernel and usually the availability of those drivers depend on contributions from the manufacturer of those components to the open source community. We from the Kernel Team commit ourselves to enable the support for as many devices as we can, therefore as soon as a device driver is available in the upstream Linux kernel it will usually be enabled in the following Ubuntu releases. If you are using the latest LTS release, when enabled in a later release, drivers will become available via the HWE kernel.

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233

Did the AppArmor stuff land on 6.15?

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234

unfortunately it did not Snapd STILL requires out-of-tree apparmor patches for strict confinement - #60 by A333 - snapd - snapcraft.io

there seem to be something holding it back still, it is unclear to me what is holding it back atm

235

Hi, (previously posted here which came up as the closest match search result.)

Today I ran my ā€œlots of security patches, update nowā€ cycle. Apparently, the lowlatency kernel disappears.

apt search linux-lowlatency stops at 6.8.0-60 but -generic has a -62 and apt wants to replace my kernel.

Is there a walk through of how to ensure - before I reboot and pick up the generic kernel - Iā€™m not going to lose the lowlatency tuning?

(I installed 22.04 LTS with the lowlatency kernel and updated to 24.04 LTS with the lowlatency kernel - Iā€™ve not been really aware of any concrete developments that indicated it was being removed.)

Thanks,

ā€“ Peter

Post-script: I remembered that the boot menu would have the previous kernel still, so I stopped panicking. However, I did find the system booted automatically to -generic rather than -lowlatency and I had to select -lowlatency by hand from the boot menu, so the question still stands.

236

Reading up in the post you linked, the Low Latency kernel is eventually going to be deprecated as the -generic kernel acts as a low latency kernel with preempt=full and threadirqs added to the boot parameters, so thereā€™s no real reason to carry the -lowlatency flavor of the kernel anymore.

237

I remember a note that said that the latest kernel available would be used for the new release. is it still true? So 25.10 will have the 17.x kernel?

239

Thanks - the generic already has threadirqs enabled, so Iā€™d just add preempt=full?

240

Yes. See Fine-Tuning the Ubuntu 24.04 Kernel for low latency, throughput, and power efficiency - Project Discussion / Kernel - Ubuntu Community Hub

241

OK, thanks ā€“ the addition settings, of course, are needed regardless of which kernel is installed. Itā€™s good to see them set out clearly, though.

242
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243

Hi all,

Iā€™m working on adapting the Ubuntu kernel for Raspberry Pi to include the latest changes for the imx296 camera sensor. Iā€™ve successfully compiled the kernel and generated the imx296.ko driver module, but Iā€™m running into issues when trying to load it on the Raspberry Pi.
Issue

When I try to load the module using insmod, I get the following error:

insmod: ERROR: could not insert module /$PATH/imx296.ko: Invalid module format

If I try to force the load with sudo modprobe -f imx296, dmesg reports:

[ 945.543990] imx296: disagrees about version of symbol module_layout

What Iā€™ve Done So Far

Based on my research, this issue typically relates to a mismatch between the kernel version and the module build configuration (symbol versioning).

On the Raspberry Pi, uname -a gives:

Linux rpi5-obc 6.8.0-1024-raspi #28-Ubuntu SMP PREEMPT_DYNAMIC Thu Apr 17 12:20:20 UTC 2025 aarch64 aarch64 aarch64 GNU/Linux

On my host machine (Ubuntu Noble), I cloned the Ubuntu kernel repo and checked out the following tag:

Ubuntu-raspi-6.8.0-1024.28
commit 71b6266113459ef62809189e5de61d54ebf80504

Then I configured and built the kernel module with:

export ARCH=arm64
export CROSS_COMPILE=aarch64-linux-gnu-
make bcm2712_defconfig
make modules

I copied the resulting imx296.ko file to the Pi and tried to insert it.

My Questions

Am I using the correct kernel version and git tag to match what's running on my Raspberry Pi?

Is my overall kernel module build process correct for targeting the Raspberry Pi 5 running Ubuntu?

Is there anything Iā€™m missing (e.g., matching kernel configs, headers, module.symvers, etc.) to ensure compatibility between the built module and the Piā€™s kernel?

Thanks in advance for any help!

244

The linux-lowlatency 6.8 kernels in Noble 24.04 will continue to exist as a separate kernel build. Although the 6.8 kernels already had the changes that allowed it to be configured for a lowlatency system we decided to not make any packaging changes to 24.04. The deprecation of the linux-lowlatency kernel as a separate build has been done only in 25.04 (see Release Notes). Therefore, if you stay with the GA 6.8 linux-lowlatency kernel and donā€™t switch to the HWE kernel (linux-lowlatency-hwe-24.04) you shouldnā€™t need to change anything in your system.

Even though the linux-generic and linux-lowlatency kernels have the same ABI numbers, they are separate packages which can be promoted to noble-updates at different times, thatā€™s why you see the lowlatency kernel lagging behind at this moment but it should catch up over the next couple of days. Regarding apt trying to replace -lowlatency with -generic, that shouldnā€™t happen as we havenā€™t done any package change that should cause it. Could you please open a bug report and provide us logs or apt output for us to look into it?

Regarding the order that grub will pick the default kernel for you, I suspect itā€™s ordering the kernels by ABI so thatā€™s why you would see -generic coming first at this time. Usually users donā€™t have the -generic and -lowlatency kernels installed at the same time, if you still want to keep the -generic kernel installed as a fallback but always boot the -lowlatency by default I would recommend looking into the grub configs available for setting the default kernel priority.

245

I havenā€™t build a Pi kernel in a while but i suspect this is the wrong config.

Not sure how much the process changed but the older docs for this are at:

https://wiki.ubuntu.com/Kernel/BuildYourOwnKernel#Modifying_the_configuration

I.e you would use fakeroot debian/rules editconfig to change the configuration ā€¦

246

Regarding apt trying to replace -lowlatency with -generic

This was just the ā€œon bootā€ scenario, I think:

Regarding the order that grub will pick the default kernel for you, I suspect itā€™s ordering the kernels by ABI so thatā€™s why you would see -generic coming first at this time.

That is, I just happened to check the kernel after theyā€™d got out of step.

Iā€™ll raise I bug if I see -lowlatency actually being removed, which didnā€™t happen.

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