linuxManualConfig: keep *.dtsi in dev output

[qbisi]

I found it very hard compiling out-of-tree devicetree in nixpkgs (not the devicetree overlay blob) , since most of the third-part devicetree require the .dtsi include file under arch/"$arch"/boot/dts directory which will be deleted during cleanup phase.
So one have to download and extract the kernel source again (and maybe patch the souce again).

Currently, the standard way to support out-of-tree board is to patch the kernel source, including copying the devicetree source file, patching the makefile. Which is not a vanilla work.

With this patch, and also some modification on nixos/device-tree module , we can support out-of-tree boards with the given dts file easily.

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandboxing enabled in nix.conf? (See Nix manual)
  • sandbox = relaxed
  • sandbox = true
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 25.05 Release Notes (or backporting 24.11 and 25.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

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[K900]

It may be a better option to just use kernel.src for this?

[qbisi]

the *.dtsi files can also be found under scripts/dtc/include-prefixes/ .So i will close this pr.

[qbisi]

the *.dtsi files can also be found under scripts/dtc/include-prefixes/ , but they are symlink to *.dtsi files under $buildRoot/arch/$linuxArch/boot/dts,
if the source is not kept, symlink will be deleted.

[qbisi]

@K900

Two reason for not using kernel.src.

1. src may be either tarball or directory, if src is a tarball then ${kernel.src}/arch/$linuxArch/boot/dts is not a directory.
2. kernel src are often patched, if patches including modifying *.dtsi files, then ${kernel.src} is not the correct source.

Finaly, we have to do unpack/patch/install jobs to make a source package including *.dtsi files.
Which is exactly what should the linux^dev package do.

[alyssais]

Two reason for not using kernel.src.

1. src may be either tarball or directory, if src is a tarball then ${kernel.src}/arch/$linuxArch/boot/dts is not a directory.

2. kernel src are often patched, if patches including modifying *.dtsi files, then  ${kernel.src} is not the correct source.

lib.srcOnly exists to get you the unpacked, patched sources.

[qbisi]

Directory scripts/dtc/include-prefixes take responsible for compiling out-of-tree dts.

Nixos have a device-tree module utilizing this directoy in linux^dev for compiling dtbo.

nixpkgs/nixos/modules/hardware/device-tree.nix

Line 81 in 67669fe

includePaths = ["${lib.getDev cfg.kernelPackage}/lib/modules/${cfg.kernelPackage.modDirVersion}/source/scripts/dtc/include-prefixes"] ++ cfg.dtboBuildExtraIncludePaths;

So why not keeping the *.dtsi file for compiling dtb.