Octoprint vcgencmd patch (#213201)

* octoprint: add tmpfile.d rule for read-access to /dev/vchiq for vcgencmd

fixes #210629

Signed-off-by: Florian Brandes <florian.brandes@posteo.de>

* Update pkgs/applications/misc/octoprint/default.nix

---------

Signed-off-by: Florian Brandes <florian.brandes@posteo.de>
Co-authored-by: Nick Cao <nickcao@nichi.co>

nixos/modules/services/misc/octoprint.nix

@@ -106,6 +106,9 @@ in
 
     systemd.tmpfiles.rules = [
       "d '${cfg.stateDir}' - ${cfg.user} ${cfg.group} - -"
+      # this will allow octoprint access to raspberry specific hardware to check for throttling
+      # read-only will not work: "VCHI initialization failed" error
+      "a /dev/vchiq - - - - u:octoprint:rw"
     ];
 
     systemd.services.octoprint = {

pkgs/applications/misc/octoprint/default.nix

@@ -82,6 +82,10 @@ let
 
               # requires octoprint itself during tests
               doCheck = false;
+              postPatch = ''
+                substituteInPlace octoprint_pi_support/__init__.py \
+                  --replace /usr/bin/vcgencmd ${self.pkgs.libraspberrypi}/bin/vcgencmd
+              '';
             };
           }
         )