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

From: Efraim Flashner <[email-masked]>
Date: Sun, 12 Apr 2020 00:11:52 +0300

On Sat, Apr 11, 2020 at 10:59:10PM +0200, Ludovic Courtès wrote:
> Hi Florian,
> 
> "pelzflorian (Florian Pelz)" <[email-masked]> 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 <[email-masked]>
> > 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))))

You don't need both of these lines. If it's a one-shot service then it
shouldn't respawn when it finishes, just when something else needs it
again.

>  
> @@ -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.

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