Kernel version numbering

Hey all, I a wondering about the version number of toradex linux kernels.

In particular, it seems the current branch is toradex_5.15-2.2.x-imx. There, 5.15 refers to the upstream linux version AFAICS, but what does 2.2.x mean here? Some BSP?

Furthermore, looking at recent branches, I see:

  remotes/toradex/toradex_5.0.y
  remotes/toradex/toradex_5.15-2.0.x-imx
  remotes/toradex/toradex_5.15-2.1.x-imx
  remotes/toradex/toradex_5.15-2.2.x-imx
  remotes/toradex/toradex_5.2.y
  remotes/toradex/toradex_5.3.y
  remotes/toradex/toradex_5.4-2.1.x-imx
  remotes/toradex/toradex_5.4-2.3.x-imx

Some of these have no 2.x version included, and some do. Also, I see 5.4-2.3.x, which has an older kernel version but a newer whatever that second version is than the current 5.15-2.2.x. Is some code downgraded there?

One reason for asking is that the 5.4-2.3.x branch has an ar1335.c camera driver which is not present in 5.15-2.2.x, so I wonder if that got added in “2.3.x” and is therefore not present in the 5.15-2.2.x?

Hi matthijs,

The versions mentioned here come from the SoC downstream vendor branch. Aside from Toradex’s changes/fixes to the vendor branches, we simply follow what the vendor does with their versions. In your example, these are Toradex kernel downstream NXP branches.

Regards,
João Paulo

Thanks, that is helpful. With that I found this page from NXP which documents the NXP BSP versions, which correspond to the toradex kernel branches (including the upstream kernel version).

In particular the document i.MX Linux® Release Notes (found by clikcing documentation → check “Release notes” → select “i.MX Linux® Release Notes”) also has a revision history of the document (nearly the last page), which shows that for each new kernel version, the second version number starts at 1.0.0 again (or sometimes 2.0.0 for some reason), which suggests to me that the second version number only has meaning within a particular kernel version number (in other words, the 2.2.x in toradex_5.4-2.2.x-imx and toradex_5.15-2.2.x-imx do not actually refer to the same version, and thus the 2.3 in toradex_5.4-2.3.x-imx is not considered newer than the toradex_5.15-2.2.x-imx).

So I think I now understand the version numbering better, thanks!

One reason for asking is that the 5.4-2.3.x branch has an ar1335.c camera driver which is not present in 5.15-2.2.x, so I wonder if that got added in “2.3.x” and is therefore not present in the 5.15-2.2.x?

As for this particular question, I noticed in the git log that the ar1335.c (and ar0521) driver was added by toradex (based on git author email domain), so it probably is not included in the NXP BSP, and I assume that toradex later decided to not add the same patch for 5.15 (and instead moved the entire ar0521 driver to a yocto layer - I already had that one working). Just FYI.

Hi @matthijs ,

Thanks for the information.

If I understand you right, it is working now. Correct?

Best Regards
Kevin

Yes, I’ve marked @joao.tx’s answer as the solution. Thanks!

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