transformations: nvidia: Allow specifying display manager in ‘#:configure-xorg?’.

* nonguix/transformations.scm (nonguix-transformation-nvidia): Allow passing
display manager service type to ‘#:configure-xorg?’.
* README.org (System setup): Update docstring.

2 files changed, 32 insertions, 7 deletions

diff --git a/README.org b/README.org
index d005d79..576b535 100644
--- a/README.org
+++ b/README.org
@@ -250,8 +250,10 @@ Procedure =nonguix-transformation-nvidia= is defined in the
   KERNEL-MODE-SETTING? (default: #t) is required for Wayland and rootless Xorg
   support.
 
-  CONFIGURE-XORG? (default: #f) is required for Xorg display managers.  Currently
-  this argument configures the one used by '%desktop-services', GDM or SDDM.
+  CONFIGURE-XORG? (default: #f) is required for Xorg display managers.  When
+  setting to #t, it configures the one specified by '%desktop-services'.  If you
+  set up the display manager on your own, use its service type instead,
+  'sddm-service-type', for example.
 
   Use 'replace-mesa', for application setup out of the operating system
   declaration.
@@ -283,11 +285,20 @@ variable =%my-os=:
 
 - Xorg environmnet: =#:configure-xorg?=:
 
+    Set to =#t= when you're using =%desktop-services=.
+
     #+begin_src scheme
       ((nonguix-transformation-nvidia #:configure-xorg? #t)
        %my-os)
     #+end_src
 
+    Specify service type of your display manager otherwine.
+
+    #+begin_src scheme
+      ((nonguix-transformation-nvidia #:configure-xorg? sddm-service-type)
+       %my-os)
+    #+end_src
+
 Full example below, using =compose= so that other system transformations can be
 mixed in:
 
diff --git a/nonguix/transformations.scm b/nonguix/transformations.scm
index 043b6d7..e31bbce 100644
--- a/nonguix/transformations.scm
+++ b/nonguix/transformations.scm
@@ -2,6 +2,7 @@
 ;;; Copyright © 2025 Hilton Chain <hako@ultrarare.space>
 
 (define-module (nonguix transformations)
+  #:use-module (ice-9 match)
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-26)
   #:use-module (guix channels)
@@ -116,8 +117,10 @@ with supported graphics cards.
 KERNEL-MODE-SETTING? (default: #t) is required for Wayland and rootless Xorg
 support.
 
-CONFIGURE-XORG? (default: #f) is required for Xorg display managers.  Currently
-this argument configures the one used by '%desktop-services', GDM or SDDM.
+CONFIGURE-XORG? (default: #f) is required for Xorg display managers.  When
+setting to #t, it configures the one specified by '%desktop-services'.  If you
+set up the display manager on your own, use its service type instead,
+'sddm-service-type', for example.
 
 Use 'replace-mesa', for application setup out of the operating system
 declaration."
@@ -150,6 +153,19 @@ declaration."
                              nvidia-module-590))
                         (modprobe nvidia-modprobe-590))))))
 
+  (define %xorg-extension
+    (and=> configure-xorg?
+           (match-lambda
+             (#t
+              (set-xorg-configuration
+               (xorg-configuration
+                 (modules (list driver)))))
+             (display-manager
+              (set-xorg-configuration
+               (xorg-configuration
+                 (modules (list driver)))
+               display-manager)))))
+
   (lambda (os)
     (operating-system
       (inherit os)
@@ -176,9 +192,7 @@ declaration."
                 (G_ "no NVIDIA service configuration available for '~a'~%")
                 (package-name driver)))
           ,@(if configure-xorg?
-                (list (set-xorg-configuration
-                       (xorg-configuration
-                         (modules (list driver)))))
+                (list %xorg-extension)
                 '())
           ,@(operating-system-user-services os))
         #:driver driver)))))