Linux kernel: Difference between revisions

Line 127:

{

boot.kernelPatches = [ {

name = "crashdump-config";

patch = null;

~~extraConfig~~ = ''

structuredExtraConfig = {

CRASH_DUMP y

CRASH_DUMP = lib.kernel.yes;

DEBUG_INFO y

DEBUG_INFO = lib.kernel.yes;

PROC_VMCORE y

PROC_VMCORE = lib.kernel.yes;

LOCKUP_DETECTOR y

LOCKUP_DETECTOR = lib.kernel.yes;

HARDLOCKUP_DETECTOR y

HARDLOCKUP_DETECTOR = lib.kernel.yes;

'';

};

} ];

}

</syntaxhighlight>

Another way is to create an overlay to configure either {{ic|extraConfig}} or {{ic|structuredExtraConfig}}. This allows for more flexibility, since you can basically override any available kernel option<ref>[https://github.com/NixOS/nixpkgs/blob/e6db435973160591fe7348876a5567c729495175/pkgs/os-specific/linux/kernel/generic.nix#L11-L56<tt>pkgs/os-specific/linux/kernel/generic.nix#L11-L56</tt>]</ref>. Using {{ic|structuredExtraConfig}} is recommended as it checks if the configured option are correct~~. You may also want to set {{ic|ignoreConfigErrors}} to avoid {{ic|error: unused option}} during builds~~.

Alternatively, you can pass a string as <code>extraConfig</code>, with option names and answers formatted like so:

<pre>

CRASH_DUMP y

DEBUG_INFO y

PROC_VMCORE y

LOCKUP_DETECTOR y

HARDLOCKUP_DETECTOR y

</pre>

Another way is to create an overlay to configure either {{ic|extraConfig}} or {{ic|structuredExtraConfig}}. This allows for more flexibility, since you can basically override any available kernel option<ref>[https://github.com/NixOS/nixpkgs/blob/e6db435973160591fe7348876a5567c729495175/pkgs/os-specific/linux/kernel/generic.nix#L11-L56<tt>pkgs/os-specific/linux/kernel/generic.nix#L11-L56</tt>]</ref>. Using {{ic|structuredExtraConfig}} is recommended as it checks if the configured option are correct.

{{file|/etc/nixos/configuration.nix|nix|<nowiki>

Line 152:

Line 163:

SCHED_MUQSS = yes;

};

ignoreConfigErrors = true;

ignoreConfigErrors = true; # not necessarily a good idea

});

})

Line 159:

Line 170:

}

</nowiki>}}

If the kernel config fails to build with messages like <code>error: unused option: DRM_I915_GVT</code>, try setting e.g. <code>DRM_I915_GVT = lib.kernel.unset</code>. Setting {{ic|ignoreConfigErrors}} will also silence these errors, at the cost of ignoring potential problems. ([https://github.com/NixOS/nixpkgs/blob/3ab9a9d12ba76f6a544c207e1364da5b3087b77c/pkgs/os-specific/linux/kernel/generate-config.pl generate-config.pl] is responsible for these; they are often produced when [https://github.com/NixOS/nixpkgs/blob/3ab9a9d12ba76f6a544c207e1364da5b3087b77c/pkgs/os-specific/linux/kernel/common-config.nix the default config] doesn't use <code>lib.kernel.option</code> for an option that is implicitly disabled by whatever change you made.)

=== Pinning a kernel version ===

@@ Line 127: / Line 127: @@
 <syntaxhighlight lang=nix>
 {
-      boot.kernelPatches = [ {
+  boot.kernelPatches = [ {
-        name = "crashdump-config";
+    name = "crashdump-config";
-        patch = null;
+    patch = null;
-        extraConfig = ''
+    structuredExtraConfig = {
-                CRASH_DUMP y
+      CRASH_DUMP = lib.kernel.yes;
-                DEBUG_INFO y
+      DEBUG_INFO = lib.kernel.yes;
-                PROC_VMCORE y
+      PROC_VMCORE = lib.kernel.yes;
-                LOCKUP_DETECTOR y
+      LOCKUP_DETECTOR = lib.kernel.yes;
-                HARDLOCKUP_DETECTOR y
+      HARDLOCKUP_DETECTOR = lib.kernel.yes;
-              '';
+    };
-        } ];
+  } ];
 }
 </syntaxhighlight>
-Another way is to create an overlay to configure either {{ic|extraConfig}} or {{ic|structuredExtraConfig}}. This allows for more flexibility, since you can basically override any available kernel option<ref>[https://github.com/NixOS/nixpkgs/blob/e6db435973160591fe7348876a5567c729495175/pkgs/os-specific/linux/kernel/generic.nix#L11-L56<tt>pkgs/os-specific/linux/kernel/generic.nix#L11-L56</tt>]</ref>. Using {{ic|structuredExtraConfig}} is recommended as it checks if the configured option are correct. You may also want to set {{ic|ignoreConfigErrors}} to avoid {{ic|error: unused option}} during builds.
+Alternatively, you can pass a string as <code>extraConfig</code>, with option names and answers formatted like so:
+<pre>
+CRASH_DUMP y
+DEBUG_INFO y
+PROC_VMCORE y
+LOCKUP_DETECTOR y
+HARDLOCKUP_DETECTOR y
+</pre>
+Another way is to create an overlay to configure either {{ic|extraConfig}} or {{ic|structuredExtraConfig}}. This allows for more flexibility, since you can basically override any available kernel option<ref>[https://github.com/NixOS/nixpkgs/blob/e6db435973160591fe7348876a5567c729495175/pkgs/os-specific/linux/kernel/generic.nix#L11-L56<tt>pkgs/os-specific/linux/kernel/generic.nix#L11-L56</tt>]</ref>. Using {{ic|structuredExtraConfig}} is recommended as it checks if the configured option are correct.
 {{file|/etc/nixos/configuration.nix|nix|<nowiki>
@@ Line 152: / Line 163: @@
              SCHED_MUQSS = yes;
            };
-           ignoreConfigErrors = true;
+           ignoreConfigErrors = true; # not necessarily a good idea
          });
        })
@@ Line 159: / Line 170: @@
 }
 </nowiki>}}
+If the kernel config fails to build with messages like <code>error: unused option: DRM_I915_GVT</code>, try setting e.g. <code>DRM_I915_GVT = lib.kernel.unset</code>. Setting {{ic|ignoreConfigErrors}} will also silence these errors, at the cost of ignoring potential problems. ([https://github.com/NixOS/nixpkgs/blob/3ab9a9d12ba76f6a544c207e1364da5b3087b77c/pkgs/os-specific/linux/kernel/generate-config.pl generate-config.pl] is responsible for these; they are often produced when [https://github.com/NixOS/nixpkgs/blob/3ab9a9d12ba76f6a544c207e1364da5b3087b77c/pkgs/os-specific/linux/kernel/common-config.nix the default config] doesn't use <code>lib.kernel.option</code> for an option that is implicitly disabled by whatever change you made.)
 === Pinning a kernel version ===