bug#40538: installer: Support uvesafb to install on machines without KMS.

[Ludovic Courtès]

Hi Florian,

"pelzflorian (Florian Pelz)" <address@hidden> skribis:

> Please consider the attached patch.  I chose to go without
> kernel-module-loader-service (only copying its requirements field)
> because I do not know how to conditionally extend or start another
> Shepherd service from an activation snippet.
>
> I tested it on QEMU with and without nomodeset.  With a previous Guix
> System install image, it stayed black when adding a nomodeset kernel
> parameter.  I will test again on real hardware now, but previous
> testing of uvesafb-enabled installer images proved successful unlike
> non-uvesafb images.

Great.

> From 85a95ce758384979a0aae3bc9065197c74862b4b Mon Sep 17 00:00:00 2001
> From: Florian Pelz <address@hidden>
> Date: Sat, 11 Apr 2020 18:56:37 +0200
> Subject: [PATCH] installer: Load uvesafb kernel module.
> MIME-Version: 1.0
> Content-Type: text/plain; charset=UTF-8
> Content-Transfer-Encoding: 8bit
>
> Fixes <https://bugs.gnu.org/40538>.
>
> Machines without Kernel Mode Setting (those with many old and current AMD
> GPUs, SiS GPUs, …) need uvesafb to show the GUI installer.  Some may also need
> a kernel parameter like nomodeset or vga=793, but we leave that for the user
> to specify in GRUB.
>
> * gnu/system/install.scm (uvesafb-shepherd-service): New procedure.
> (uvesafb-service-type): New variable.
> (%uvesafb-service): New variable.
> (%installation-services): Add it.

I made the following adjustments.

I also confirmed that everything goes well in QEMU, but obviously we’ll
have to test on hardware.

Let’s publish an RC2 tomorrow so we can get feedback.

Thank you!

Ludo’.

diff --git a/gnu/system/install.scm b/gnu/system/install.scm
index 73a013bed0..203a085bcd 100644
--- a/gnu/system/install.scm
+++ b/gnu/system/install.scm
@@ -276,6 +276,7 @@ the user's target storage device rather than on the RAM 
disk."
 (define %configuration-template-service
   (service configuration-template-service-type #t))
 
+
 (define %nscd-minimal-caches
   ;; Minimal in-memory caching policy for nscd.
   (list (nscd-cache (database 'hosts)
@@ -295,21 +296,18 @@ the user's target storage device rather than on the RAM 
disk."
 ;; support Kernel Mode Setting.  Otherwise kmscon is missing /dev/fb0.
 (define (uvesafb-shepherd-service _)
   (list (shepherd-service
-         (documentation "Load uvesafb.")
+         (documentation "Load the uvesafb kernel module.")
          (provision '(uvesafb))
          (requirement '(file-systems))
-         (start (with-imported-modules (source-module-closure '((guix utils)))
-                  #~(begin
-                      (use-modules (guix utils))
-                      (lambda ()
-                        ;; uvesafb is only supported on x86 and x86_64.
-                        (if (member (%current-system)
-                                    '("x86_64-linux" "i686-linux"))
-                            (invoke #+(file-append kmod "/bin/modprobe")
-                                    "uvesafb"
-                                    (string-append "v86d=" #$v86d "/sbin/v86d")
-                                    "mode_option=1024x768")
-                            #t)))))
+         (start #~(lambda ()
+                    ;; uvesafb is only supported on x86 and x86_64.
+                    (or (not (and (string-suffix? "linux-gnu" %host-type)
+                                  (or (string-prefix? "x86_64" %host-type)
+                                      (string-prefix? "i686" %host-type))))
+                        (invoke #+(file-append kmod "/bin/modprobe")
+                                "uvesafb"
+                                (string-append "v86d=" #$v86d "/sbin/v86d")
+                                "mode_option=1024x768"))))
          (respawn? #f)
          (one-shot? #t))))
 
@@ -319,11 +317,10 @@ the user's target storage device rather than on the RAM 
disk."
    (extensions
     (list (service-extension shepherd-root-service-type
                              uvesafb-shepherd-service)))
+   (description
+    "Load the @code{uvesafb} kernel module with the right options.")
    (default-value #t)))
 
-(define %uvesafb-service
-  (service uvesafb-service-type))
-
 (define %installation-services
   ;; List of services of the installation system.
   (let ((motd (plain-file "motd" "
@@ -451,7 +448,7 @@ Access documentation at any time by pressing Alt-F2.\x1b[0m
           ;; current AMD GPUs, SiS GPUs, ...) need uvesafb to show the GUI
           ;; installer.  Some may also need a kernel parameter like nomodeset
           ;; or vga=793, but we leave that for the user to specify in GRUB.
-          %uvesafb-service)))
+          (service uvesafb-service-type))))
 
 (define %issue
   ;; Greeting.