* Re: Questions about SLTS v4.19
2025-01-22 9:16 Questions about SLTS v4.19 Luca Weiss
@ 2025-01-25 6:34 ` Jan Kiszka
2025-01-31 11:59 ` [cip-dev] " Pavel Machek
1 sibling, 0 replies; 3+ messages in thread
From: Jan Kiszka @ 2025-01-25 6:34 UTC (permalink / raw)
To: Luca Weiss, cip-dev; +Cc: karsten
Hi Luca,
On 22.01.25 10:16, Luca Weiss wrote:
> Hi,
>
> I've got some questions regarding the SLTS v4.19 tree which I couldn't
> find an answer to on the website.
>
> As Fairphone, one of our Android devices, Fairphone 4 is running on a
> 4.19 kernel fork which was provided by Qualcomm. Unfortunately
> linux-stable support has run out and while we're looking into upgrading
> the kernel to a newer version, for now we're stuck with 4.19.
>
> Since CIP will continue maintaining the 4.19 kernel for the foreseeable
> future, we were thinking about starting to merge the v4.19 CIP releases
> into our tree, and continuing to do that for the foreseable future.
>
> But it's not clear to me what is actually in scope for the 4.19 branch.
> At
> https://wiki.linuxfoundation.org/civilinfrastructureplatform/cipkernelmaintenance
> I see the text "For the 4.4 branch, the architectures we've committed to
> so far are arm (32-bit) and x86_64." but no info about 4.19, whether
> arm64 will be included, which is what our device is running on.
>
We started to support arm64 with 4.19, see our reference hardware matrix
[1] and, more importantly, our configs [2] for the various versions.
> And also while we're not a CIP member we'd like to know whether we can
> consider the CIP branches to be reasonably equivalent to the
> linux-stable branches, for example where we can assume that all known
> (security) issues will be getting the fixes backported, or how else it
> might differ from regular LTS.
The CIP kernel is not a direct continuation of the LTS kernel. As we
have limited resources, we focus on configurations and, thus,
subsystems, drivers etc. that our members bring forward as relevant. If
you are lucky, you already have a large overlap with a checked-in config
[3]. If only little is missing, I would still suggest to openly discuss
this with us. The privilege to decide over expanding the support is with
the members, but maybe there is some common interest nevertheless.
Another difference, though no longer relevant for 4.19, is that we
accept non-invasive backports of hardware support that was merged into
mainline, just after a specific CIP kernel series. This helps to bridge
the time between two CIP kernels (usually 2 years apart) while avoiding
ABI breakages via downstream patches when moving to a newer mainline or
CIP kernel with your device.
You should also to have a look at what we just wrote up on the CIP
kernel ecosystem at [4]. Feel free to follow up if you have further
questions.
Best regards,
Jan
[1]
https://wiki.linuxfoundation.org/civilinfrastructureplatform/ciptesting/cipreferencehardware
[2] https://gitlab.com/cip-project/cip-kernel/cip-kernel-config
[3]
https://gitlab.com/cip-project/cip-kernel/cip-kernel-config/-/tree/master/4.19.y-cip/arm64?ref_type=heads
[4]
https://www.cip-project.org/blog/2025/01/13/kernel-6-12-will-have-10-years-support-via-cip-are-all-your-maintenance-problems-solved
--
Siemens AG, Foundational Technologies
Linux Expert Center
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [cip-dev] Questions about SLTS v4.19
2025-01-22 9:16 Questions about SLTS v4.19 Luca Weiss
2025-01-25 6:34 ` Jan Kiszka
@ 2025-01-31 11:59 ` Pavel Machek
1 sibling, 0 replies; 3+ messages in thread
From: Pavel Machek @ 2025-01-31 11:59 UTC (permalink / raw)
To: cip-dev; +Cc: karsten
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hi!
> I've got some questions regarding the SLTS v4.19 tree which I couldn't
> find an answer to on the website.
>
> As Fairphone, one of our Android devices, Fairphone 4 is running on a
> 4.19 kernel fork which was provided by Qualcomm. Unfortunately
> linux-stable support has run out and while we're looking into upgrading
> the kernel to a newer version, for now we're stuck with 4.19.
>
> Since CIP will continue maintaining the 4.19 kernel for the foreseeable
> future, we were thinking about starting to merge the v4.19 CIP releases
> into our tree, and continuing to do that for the foreseable future.
That sounds like a reasonable plan. Similar to 4.4-st, 4.19-st branch
should be best option for that (to be published soon).
> But it's not clear to me what is actually in scope for the 4.19 branch.
> At
> https://wiki.linuxfoundation.org/civilinfrastructureplatform/cipkernelmaintenance
> I see the text "For the 4.4 branch, the architectures we've committed to
> so far are arm (32-bit) and x86_64." but no info about 4.19, whether
> arm64 will be included, which is what our device is running on.
Arm64 should be in scope.
> And also while we're not a CIP member we'd like to know whether we can
> consider the CIP branches to be reasonably equivalent to the
> linux-stable branches, for example where we can assume that all known
> (security) issues will be getting the fixes backported, or how else it
> might differ from regular LTS.
Well, you can't rely on regular LTS to assume all issues are fixed,
and you should not rely on that with 4.19-st, either... but it should
be good base. We -cip/-st trees don't get as much testing as stable
trees do, so if you could set up testing on your hardware, that would
be good.
Of course, you are welcome to join CIP project, then you'll get chance
to improve project direction, will be able to put hw in the test labs,
etc ;-).
Now, not speaking for CIP or Denx... Well supported phone would be fun
to play with, but I'm not sure if hardware is easy to get in czech
republic, or if it is easy to get support for anything but Android...?
Best regards,
Pavel
--
DENX Software Engineering GmbH, Managing Director: Erika Unter
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
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