[Letux-kernel] New LetuxOS kernel trees for Replicant

[H. Nikolaus Schaller]

> Am 29.06.2019 um 22:02 schrieb Andreas Kemnade <andreas at kemnade.info>:
> 
> This with CONFIG_LOCALVERSION_AUTO=y,
> then we know which kernel we are using.

I just recognised that we are maybe talking about something different...

One thing is to keep kernel trees separated and build results on the build host.

The other one is finding out which exact commit a given uImage has been built from.

This are two different questions with different answers.
CONFIG_LOCALVERSION_AUTO=y is a solution for the second one.

For the first it does not help because you need to know some unique name before
and without running the compiler.

I have chosen the branch name (because it also allows to build feature branches
or projects). This means if kernel trees are different they should have a different
branch name which requires to include the full linux subversion numbers in the name.

There is one more issue with CONFIG_LOCALVERSION_AUTO=y. If I remember correctly,
this is also appended to the kernel name in lib/modules/kernel. This means that
every commit ends in a different directory for all the kernel modules.
Even if you just did edit the commit message and the built binary is the same.

This breaks rsyncing the kernel to the device because it always copies
everything.

Well, I have disabled some DEBUG options in letux-4.13 or so, so that we have
stripped kernel modules. Just 8MB instead of 160MB. But copying 160MB kernel
modules takes some time...

So having CONFIG_LOCALVERSION_AUTO is still a good compromise.

BR,
Nikolaus