Main Linux kernel vs Ubuntu kernel

[Shyam Saini]

> Hi All,

Hi Subhashini


> Apologies for the dull questions, I’m noob, need to learn lot more stuff.
>
>
>
> We’ve a bunch of hardware & test systems, we started this project by opting
> ubuntu distro 16.04 LTS v4.4 kernel for development of device drivers, test
> utilities.
>
>
> I’d like to know, what are the differences between the main Linux kernel and
> the kernel being used by Ubuntu?

Well, mainline kernel is development kernel which keeps changing
everyday, and in fact every
minute.

Just to give you an idea
This kernel is tested and a stable kernel is released by Greg, out of
this mainline kernel.

You can read the complete development process here:
https://www.kernel.org/doc/html/v4.17/process/howto.html

About releases:
https://www.kernel.org/category/releases.html
https://www.kernel.org/


About ubuntu kernel:
The kernel developers of ubuntu fork  or pull mainline kernel and customise it
and release their distro kernel.
You get it when you update your system.

You can read about it here:
https://help.ubuntu.com/community/Kernel
https://wiki.ubuntu.com/KernelTeam

> If I need to upgrade our drivers to latest kernel v4.17, what are the best
> possible ways? In future, is it possible for us to use the current installed
> 16.04 LTS by just upgrading the Linux kernel version?

Yes you can build mainline kernel and run in ubuntu 16.04.
https://kernelnewbies.org/FirstKernelPatch

If you get some issues(rare case) you can report them back to mailing list.

The mailing lists are subsystem specific.
For example:
for networking related issues you can mail to netdev at vger.kernel.org.
Find all the lists here:
http://vger.kernel.org/vger-lists.html

> Are all the Linux kernel releases are backward compatible?
yes, except for old and obsolete hardware. They get their way out of kernel tree
via staging/ directory in kernel source tree.

>
> Even Ubuntu distro has LTS, non-LTS, GA, HWE kernels, what’s the difference
> between these? Which one should be the best choice for development &
> validating the hardware?

They are ubuntu specific.

For development mainline kernel is best.

You always have option to test your hardware and report issues if any.
If mainline breaks for your hardware then you can choose any known
stable kernel version.
You can patch and test it as per your needs.

>
> Can someone clarify me on this?
>

Thanks a lot,
Shyam