[bug#53059] [PATCH] gnu: Add gpu-switch.

[bug#53059] [PATCH] gnu: Add gpu-switch.

[Jorge Acereda]

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* gnu/packages/graphics.scm (gpu-switch): New variable.
---
 gnu/packages/graphics.scm | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/gnu/packages/graphics.scm b/gnu/packages/graphics.scm
index fe35aaad2d..b5b50f6192 100644
--- a/gnu/packages/graphics.scm
+++ b/gnu/packages/graphics.scm
@@ -27,6 +27,7 @@
 ;;; Copyright © 2021 Andy Tai <atai@atai.org>
 ;;; Copyright © 2021 Ekaitz Zarraga <ekaitz@elenq.tech>
 ;;; Copyright © 2021 Vinicius Monego <monego@posteo.net>
+;;; Copyright © 2022 Jorge Acereda <jacereda@gmail.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -113,6 +114,7 @@ (define-module (gnu packages graphics)
   #:use-module (guix build-system meson)
   #:use-module (guix build-system python)
   #:use-module (guix build-system qt)
+  #:use-module (guix build-system trivial)
   #:use-module (guix download)
   #:use-module (guix git-download)
   #:use-module (guix hg-download)
@@ -2011,3 +2013,39 @@ (define-public monado
 such as VR and AR on mobile, PC/desktop, and any other device.  Monado aims to be
 a complete and conforming implementation of the OpenXR API made by Khronos.")
     (license license:boost1.0)))
+
+(define-public gpu-switch
+  (package
+    (name "gpu-switch")
+    (version "2017-04-28")
+    (source
+     (origin
+       (method git-fetch)
+       (uri (git-reference
+             (url "https://github.com/0xbb/gpu-switch")
+             (commit "a365f56d435c8ef84c4dd2ab935ede4992359e31")))
+       (file-name (git-file-name name version))
+       (sha256
+        (base32 "1jnh43nijkqd83h7piq7225ixziggyzaalabgissyxdyz6szcn0r"))))
+    (build-system trivial-build-system)
+    (arguments
+     `(#:modules ((guix build utils))
+       #:builder
+       (begin
+         (use-modules (guix build utils))
+         (let ((out (assoc-ref %outputs "out"))
+               (gpu-switch (search-input-file %build-inputs "gpu-switch"))
+               (readme (search-input-file %build-inputs "README.md")))
+           (install-file gpu-switch (string-append out "/bin"))
+           (install-file readme (string-append out "/share/doc/gpu-switch-" ,version))
+           #t))))
+    (home-page "https://github.com/0xbb/gpu-switch")
+    (synopsis "GPU switcher for dual-GPU MacBook Pro models")
+    (description
+     "Switch between the integrated and dedicated GPU of dual-GPU MacBook Pro
+models for the next reboot.
+
+It aims to remove the need of booting into OS X and running gfxCardStatus
+v2.2.1 to switch to the integrated card.")
+    (license license:expat)))
+
-- 
2.34.0

[bug#53059] [PATCH] gnu: Add gpu-switch.

[Maxime Devos]

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Hi,

Looking at <https://github.com/0xbb/gpu-switch/blob/master/gpu-switch>,
it appears that it uses 'chattr', 'mount', 'grep', 'cat' and
'basename'. So the corresponding packages would need to be added
to 'inputs' and a few 'substitute*' are required such that gpu-switch
doesn't require 'chattr' & friends to be in the environment.

/sys/firmware/efi/efivars is rather Linux-specific, presumably
non-existent on the hurd, so the hurd systems need to be removed from
supported-systems.

> +    (name "gpu-switch")
> +    (version "2017-04-28")
> +    (source
> +     (origin
> +       (method git-fetch)
> +       (uri (git-reference
> +             (url "https://github.com/0xbb/gpu-switch")
> +             (commit "a365f56d435c8ef84c4dd2ab935ede4992359e31")))

Where did you get this version/commit pair from? I'm not seeing it on
<https://github.com/0xbb/gpu-switch/releases>.

Greetings,
Maxime.

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[bug#53059] [PATCH] gnu: Add gpu-switch.

[Maxime Devos]

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[Re-adding debbugs to CC]

Jorge Acereda schreef op vr 07-01-2022 om 02:02 [+0100]:
> [...]
> > 
> > /sys/firmware/efi/efivars is rather Linux-specific, presumably
> > non-existent on the hurd, so the hurd systems need to be removed from
> > supported-systems.
> 
> Would it be better in linux.scm instead?

While it currently is Linux-specific, in principle it could be ported
to the Hurd, a BSD or Windows or whatever -- in fact, looking at
https://github.com/0xbb/gpu-switch, it appears to support ‘osx’ and
Windows.

linux.scm is more for Linux kernel modules, the Linux kernel, userspace
bindings to kernel syscalls ...

There probably are a few misplaced packages in linux.scm.

Greetings,
Maxime

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[bug#53059] [PATCH v2] gnu: Add gpu-switch.

[Jorge Acereda]

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The package version is the same one used in nixpkgs (current tip).
Should I add some "unstable" string somewhere?  Also, I'm pretty sure
I overcomplicated things, there must be some easier way to patch the
executable paths.

* gnu/packages/graphics.scm (gpu-switch): New variable.
---
 gnu/packages/graphics.scm | 58 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 57 insertions(+), 1 deletion(-)

diff --git a/gnu/packages/graphics.scm b/gnu/packages/graphics.scm
index fe35aaad2d..d425a18c18 100644
--- a/gnu/packages/graphics.scm
+++ b/gnu/packages/graphics.scm
@@ -27,6 +27,7 @@
 ;;; Copyright © 2021 Andy Tai <atai@atai.org>
 ;;; Copyright © 2021 Ekaitz Zarraga <ekaitz@elenq.tech>
 ;;; Copyright © 2021 Vinicius Monego <monego@posteo.net>
+;;; Copyright © 2022 Jorge Acereda <jacereda@gmail.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -113,12 +114,14 @@ (define-module (gnu packages graphics)
   #:use-module (guix build-system meson)
   #:use-module (guix build-system python)
   #:use-module (guix build-system qt)
+  #:use-module (guix build-system trivial)
   #:use-module (guix download)
   #:use-module (guix git-download)
   #:use-module (guix hg-download)
   #:use-module ((guix licenses) #:prefix license:)
   #:use-module (guix packages)
-  #:use-module (guix utils))
+  #:use-module (guix utils)
+  #:use-module (ice-9 match))
 
 (define-public mmm
   (package
@@ -2011,4 +2014,56 @@ (define-public monado
 such as VR and AR on mobile, PC/desktop, and any other device.  Monado aims to be
 a complete and conforming implementation of the OpenXR API made by Khronos.")
     (license license:boost1.0)))
 +
+(define-public gpu-switch
+  (package
+    (name "gpu-switch")
+    (version "2017-04-28")
+    (source
+     (origin
+       (method git-fetch)
+       (uri (git-reference
+             (url "https://github.com/0xbb/gpu-switch")
+             (commit "a365f56d435c8ef84c4dd2ab935ede4992359e31")))
+       (file-name (git-file-name name version))
+       (sha256
+        (base32 "1jnh43nijkqd83h7piq7225ixziggyzaalabgissyxdyz6szcn0r"))))
+    (build-system trivial-build-system)
+    (inputs
+     (list bash e2fsprogs util-linux grep coreutils which))
+    (arguments
+     `(#:modules ((guix build utils))
+       #:builder
+       (begin
+         (use-modules (guix build utils) (ice-9 match))
+         (let* ((out (assoc-ref %outputs "out"))
+                (gpu-switch (search-input-file %build-inputs "gpu-switch"))
+                (bin (string-append out "/bin"))
+                (out-gpu-switch (string-append bin "/gpu-switch"))
+                (readme (search-input-file %build-inputs "README.md")))
+           (install-file gpu-switch bin)
+           (for-each
+            (match-lambda
+              ((pkg . nm) (substitute* out-gpu-switch
+                            ((nm)
+                             (string-append (assoc-ref %build-inputs pkg)
+                                            "/bin/" nm)))))
+            '(("coreutils" . "basename")
+              ("bash" . "bash")
+              ("util-linux" . "mount")
+              ("which" . "which")
+              ("coreutils" . "cat")
+              ("e2fsprogs" . "chattr")
+              ("grep" . "grep")))
+           (install-file readme (string-append out "/share/doc/gpu-switch-" ,version))
+           #t))))
+    (home-page "https://github.com/0xbb/gpu-switch")
+    (synopsis "GPU switcher for dual-GPU MacBook Pro models")
+    (description
+     "Switch between the integrated and dedicated GPU of dual-GPU MacBook Pro
+models for the next reboot.
+
+It aims to remove the need of booting into OS X and running gfxCardStatus
+v2.2.1 to switch to the integrated card.")
+    (license license:expat)))
+
-- 
2.34.0

[bug#53059] [PATCH v2] gnu: Add gpu-switch.

[Maxime Devos]

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Jorge Acereda schreef op vr 07-01-2022 om 19:37 [+0100]:
> The package version is the same one used in nixpkgs (current tip).
> Should I add some "unstable" string somewhere?  Also, I'm pretty sure
> I overcomplicated things, there must be some easier way to patch the
> executable paths.

Ok, but anyone looking at the package definition of gpu-switch would
be having a hard time figuring out these reasons.  Also, the version
used by nixpkgs isn't very relevant; nixpkgs might be out-of-date.

An "-unstable" version suffix isn't very informative, and doesn't
seem correct here: there haven't been any changes in gpu-switch for
about five years, which seems rather stable to me.

I suggest having a look at ‘17.4.3 Version Numbers’ in the manual,
in particular the text about VCS vs formal releases.

Because upstream isn't formally releasing anything, using a revision
from git seems appropriate to me, but the reasons needs to be
documented with a comment.  E.g., see 'emacs-graphql-mode'.

> * gnu/packages/graphics.scm (gpu-switch): New variable.
> ---
>  gnu/packages/graphics.scm | 58 ++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 57 insertions(+), 1 deletion(-)
> 
> diff --git a/gnu/packages/graphics.scm b/gnu/packages/graphics.scm
> index fe35aaad2d..d425a18c18 100644
> --- a/gnu/packages/graphics.scm
> +++ b/gnu/packages/graphics.scm

GPUs aren't only used for graphics, see e.g.
<https://boinc.berkeley.edu/wiki/GPU_computing>.
I would put it in hardware.scm instead.

> @@ -27,6 +27,7 @@
>  ;;; Copyright © 2021 Andy Tai <atai@atai.org>
>  ;;; Copyright © 2021 Ekaitz Zarraga <ekaitz@elenq.tech>
>  ;;; Copyright © 2021 Vinicius Monego <monego@posteo.net>
> +;;; Copyright © 2022 Jorge Acereda <jacereda@gmail.com>
>  ;;;
>  ;;; This file is part of GNU Guix.
>  ;;;
> @@ -113,12 +114,14 @@ (define-module (gnu packages graphics)
>    #:use-module (guix build-system meson)
>    #:use-module (guix build-system python)
>    #:use-module (guix build-system qt)
> +  #:use-module (guix build-system trivial)
>    #:use-module (guix download)
>    #:use-module (guix git-download)
>    #:use-module (guix hg-download)
>    #:use-module ((guix licenses) #:prefix license:)
>    #:use-module (guix packages)
> -  #:use-module (guix utils))
> +  #:use-module (guix utils)
> +  #:use-module (ice-9 match))


Not needed, the use of 'match' is only at the build side.

>  
>  (define-public mmm
>    (package
> @@ -2011,4 +2014,56 @@ (define-public monado
>  such as VR and AR on mobile, PC/desktop, and any other device.  Monado aims to be
>  a complete and conforming implementation of the OpenXR API made by Khronos.")
>      (license license:boost1.0)))
>  +
> +(define-public gpu-switch
> +  (package
> +    (name "gpu-switch")
> +    (version "2017-04-28")
> +    (source
> +     (origin
> +       (method git-fetch)
> +       (uri (git-reference
> +             (url "https://github.com/0xbb/gpu-switch")
> +             (commit "a365f56d435c8ef84c4dd2ab935ede4992359e31")))
> +       (file-name (git-file-name name version))
> +       (sha256
> +        (base32 "1jnh43nijkqd83h7piq7225ixziggyzaalabgissyxdyz6szcn0r"))))
> +    (build-system trivial-build-system)
> +    (inputs
> +     (list bash e2fsprogs util-linux grep coreutils which))

I suggest bash-minimal and coreutils-minimal to reduce the closure.

> +    (arguments
> +     `(#:modules ((guix build utils))
> +       #:builder
> +       (begin
> +         (use-modules (guix build utils) (ice-9 match))
> +         (let* ((out (assoc-ref %outputs "out"))

%outputs is sort-of deprecated, it is recommended to use G-exps
instead: (let* ((out #$output) ...) ...)

> +                (gpu-switch (search-input-file %build-inputs "gpu-switch"))

Likewise, %build-inputs is deprecated, and it doesn't do the right
thing when cross-compiling, because (implicit) native inputs go before
native inputs. In this particular case, it would work, but I'd avoid
this fragility, by doing something like (let (... (inputs #$inputs)
(gpu-switch (search-input-file inputs "gpu-switch"))) ...) instead.

Personally, I'd do #$(file-append source "/gpu-switch") instead though.

> +                (bin (string-append out "/bin"))
> +                (out-gpu-switch (string-append bin "/gpu-switch"))
> +                (readme (search-input-file %build-inputs "README.md")))

Likewise.

> +           (install-file gpu-switch bin)

The shebang starts with

#!/usr/bin/env /gnu/store/[a hash]-bash-5.1.8/bin/bash

so the script depends on the system's /usr/bin/env. Can this dependency
be removed, e.g. using patch-shebang?

The script has a line

  $(/gnu/store/y5jxkx484x7s2c2n7dc8wprh5sbps7pl-coreutils-
8.32/bin/basename $0) --integrated   # Switch to the integrated GPU

but this is fragile, what if I create a symlink named "switch the gpu"
pointing to gpu-switch (without the quotes, and with the spaces)?

Then I get

$ ./switch\ the\ gpu 
/gnu/store/y5jxkx484x7s2c2n7dc8wprh5sbps7pl-coreutils-
8.32/bin/basename: extra operand 'gpu'
Try '/gnu/store/y5jxkx484x7s2c2n7dc8wprh5sbps7pl-coreutils-
8.32/bin/basename --help' for more information.
/gnu/store/y5jxkx484x7s2c2n7dc8wprh5sbps7pl-coreutils-
8.32/bin/basename: extra operand 'gpu'
Try '/gnu/store/y5jxkx484x7s2c2n7dc8wprh5sbps7pl-coreutils-
8.32/bin/basename --help' for more information.
/gnu/store/y5jxkx484x7s2c2n7dc8wprh5sbps7pl-coreutils-
8.32/bin/basename: extra operand 'gpu'
Try '/gnu/store/y5jxkx484x7s2c2n7dc8wprh5sbps7pl-coreutils-
8.32/bin/basename --help' for more information.

Can this be fixed (upstream)?  Putting "" around the $0 would probably
be enough.  Also, I thought it might be required to place -- before the
"$0" (in case the symlink is named "--help"), but it seems to work
without in my tests.  I would still recommend an -- argument though,
to make things less fragile.

> +           (for-each
> +            (match-lambda
> +              ((pkg . nm) (substitute* out-gpu-switch

I see the following line in the output of "gpu-switch"

  gpu-switch --dedi/gnu/store/y5jxkx484x7s2c2n7dc8wprh5sbps7pl-
coreutils-8.32/bin/cated    # Switch to the
dedi/gnu/store/y5jxkx484x7s2c2n7dc8wprh5sbps7pl-coreutils-
8.32/bin/cated GPU   

Likewise:

      printf "Fatal: Couldn't
/gnu/store/64d0mxsjqifrpashlhyd3rf7zm2r709x-util-linux-2.37.1/bin/mount
'${sysfs_efi_vars}'.\n" 1>&2

Seems like the substitutions are not sufficiently specific.

> +                            ((nm)
> +                             (string-append (assoc-ref %build-inputs pkg)

%build-inputs -> #$inputs? Or maybe even use search-input-file.

Also, you can substitute multiple things with a single substitute*.
E.g., 

          ;; From the manual, see (guix)Build Utilities
          (substitute* file
            (("hello")
             "good morning\n")
            (("foo([a-z]+)bar(.*)$" all letters end)
             (string-append "baz" letter end)))

> +           #t))))

Returning #true in phases is not required anymore, presumably the same
holds for #:builder.

> +    (home-page "https://github.com/0xbb/gpu-switch")
> +    (synopsis "GPU switcher for dual-GPU MacBook Pro models")
> +    (description
> +     "Switch between the integrated and dedicated GPU of dual-GPU MacBook Pro
> +models for the next reboot.

Is this specific for ‘MacBook Pro models’, or does it work for any
computer that has a certain combination of ‘integrated’ and ‘dedicated’
GPU?

> +It aims to remove the need of booting into OS X and running gfxCardStatus
> +v2.2.1 to switch to the integrated card.")

Is this v2.2.1 important?

Greetings,
Maxime.

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[bug#53059] [PATCH v3] gnu: Add gpu-switch.

[Jorge Acereda]

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* gnu/packages/graphics.scm (gpu-switch): New variable.
---
 gnu/packages/hardware.scm | 50 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/gnu/packages/hardware.scm b/gnu/packages/hardware.scm
index 28647477fe..8ec82f1297 100644
--- a/gnu/packages/hardware.scm
+++ b/gnu/packages/hardware.scm
@@ -9,6 +9,7 @@
 ;;; Copyright © 2021 Raghav Gururajan <rg@raghavgururajan.name>
 ;;; Copyright © 2021 Vinicius Monego <monego@posteo.net>
 ;;; Copyright © 2021 John Kehayias <john.kehayias@protonmail.com>
+;;; Copyright © 2022 Jorge Acereda <jacereda@gmail.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -29,6 +30,7 @@ (define-module (gnu packages hardware)
   #:use-module (gnu packages)
   #:use-module (gnu packages admin)
   #:use-module (gnu packages autotools)
+  #:use-module (gnu packages base)
   #:use-module (gnu packages bash)
   #:use-module (gnu packages compression)
   #:use-module (gnu packages check)
@@ -64,7 +66,9 @@ (define-module (gnu packages hardware)
   #:use-module (guix build-system gnu)
   #:use-module (guix build-system meson)
   #:use-module (guix build-system python)
+  #:use-module (guix build-system trivial)
   #:use-module (guix download)
+  #:use-module (guix gexp)
   #:use-module (guix git-download)
   #:use-module (guix svn-download)
   #:use-module ((guix licenses) #:prefix license:)
@@ -844,3 +848,49 @@ (define-public tpm2-tss
 libtss2-esys, libtss2-sys, libtss2-mu, libtss2-tcti-device, libtss2-tcti-swtpm
 and libtss2-tcti-mssim.")
     (license license:bsd-2)))
+
+(define-public gpu-switch
+  ;; No tagged commit.  No "Version" keyword either.
+  (let ((commit "a365f56d435c8ef84c4dd2ab935ede4992359e31")
+        (revision "1"))
+    (package
+      (name "gpu-switch")
+      (version (git-version "0" revision commit))
+      (source
+       (origin
+         (method git-fetch)
+         (uri (git-reference
+               (url "https://github.com/0xbb/gpu-switch")
+               (commit commit)))
+         (file-name (git-file-name name version))
+         (sha256
+          (base32 "1jnh43nijkqd83h7piq7225ixziggyzaalabgissyxdyz6szcn0r"))))
+      (build-system trivial-build-system)
+      (arguments
+       (list
+        #:modules '((guix build utils))
+        #:builder
+        #~(begin
+            (use-modules (guix build utils))
+            (install-file #$(file-append source "/gpu-switch")
+                          (string-append #$output "/bin"))
+            (substitute* (string-append #$output "/bin/gpu-switch")
+              (("basename") #$(file-append coreutils-minimal "/bin/basename"))
+              (("cat ") #$(file-append coreutils-minimal "/bin/cat "))
+              (("chattr") #$(file-append e2fsprogs "/bin/chattr"))
+              (("/usr/bin/env bash") #$(file-append bash-minimal "/bin/bash"))
+              (("grep") #$(file-append grep "/bin/grep"))
+              (("! mount")
+               (string-append "! " #$(file-append util-linux "/bin/mount"))))
+            (install-file
+             #$(file-append source "/README.md")
+             (string-append #$output "/share/doc/gpu-switch-" #$version)))))
+      (home-page "https://github.com/0xbb/gpu-switch")
+      (synopsis "GPU switcher for dual-GPU MacBook Pro models")
+      (description
+       "Switch between the integrated and dedicated GPU of dual-GPU MacBook Pro
+models for the next reboot.
+
+It aims to remove the need of booting into OS X and running gfxCardStatus
+v2.2.1 to switch to the integrated card.")
+      (license license:expat))))
-- 
2.34.0

[bug#53059] [PATCH v4] gnu: Add gpu-switch.

[Jorge Acereda]

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Forgot to specify supported-systems.

* gnu/packages/graphics.scm (gpu-switch): New variable.
---
 gnu/packages/hardware.scm | 51 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

diff --git a/gnu/packages/hardware.scm b/gnu/packages/hardware.scm
index 28647477fe..a8ec6567cd 100644
--- a/gnu/packages/hardware.scm
+++ b/gnu/packages/hardware.scm
@@ -9,6 +9,7 @@
 ;;; Copyright © 2021 Raghav Gururajan <rg@raghavgururajan.name>
 ;;; Copyright © 2021 Vinicius Monego <monego@posteo.net>
 ;;; Copyright © 2021 John Kehayias <john.kehayias@protonmail.com>
+;;; Copyright © 2022 Jorge Acereda <jacereda@gmail.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -29,6 +30,7 @@ (define-module (gnu packages hardware)
   #:use-module (gnu packages)
   #:use-module (gnu packages admin)
   #:use-module (gnu packages autotools)
+  #:use-module (gnu packages base)
   #:use-module (gnu packages bash)
   #:use-module (gnu packages compression)
   #:use-module (gnu packages check)
@@ -64,7 +66,9 @@ (define-module (gnu packages hardware)
   #:use-module (guix build-system gnu)
   #:use-module (guix build-system meson)
   #:use-module (guix build-system python)
+  #:use-module (guix build-system trivial)
   #:use-module (guix download)
+  #:use-module (guix gexp)
   #:use-module (guix git-download)
   #:use-module (guix svn-download)
   #:use-module ((guix licenses) #:prefix license:)
@@ -844,3 +848,50 @@ (define-public tpm2-tss
 libtss2-esys, libtss2-sys, libtss2-mu, libtss2-tcti-device, libtss2-tcti-swtpm
 and libtss2-tcti-mssim.")
     (license license:bsd-2)))
+
+(define-public gpu-switch
+  ;; No tagged commit.  No "Version" keyword either.
+  (let ((commit "a365f56d435c8ef84c4dd2ab935ede4992359e31")
+        (revision "1"))
+    (package
+      (name "gpu-switch")
+      (version (git-version "0" revision commit))
+      (source
+       (origin
+         (method git-fetch)
+         (uri (git-reference
+               (url "https://github.com/0xbb/gpu-switch")
+               (commit commit)))
+         (file-name (git-file-name name version))
+         (sha256
+          (base32 "1jnh43nijkqd83h7piq7225ixziggyzaalabgissyxdyz6szcn0r"))))
+      (build-system trivial-build-system)
+      (arguments
+       (list
+        #:modules '((guix build utils))
+        #:builder
+        #~(begin
+            (use-modules (guix build utils))
+            (install-file #$(file-append source "/gpu-switch")
+                          (string-append #$output "/bin"))
+            (substitute* (string-append #$output "/bin/gpu-switch")
+              (("basename") #$(file-append coreutils-minimal "/bin/basename"))
+              (("cat ") #$(file-append coreutils-minimal "/bin/cat "))
+              (("chattr") #$(file-append e2fsprogs "/bin/chattr"))
+              (("/usr/bin/env bash") #$(file-append bash-minimal "/bin/bash"))
+              (("grep") #$(file-append grep "/bin/grep"))
+              (("! mount")
+               (string-append "! " #$(file-append util-linux "/bin/mount"))))
+            (install-file
+             #$(file-append source "/README.md")
+             (string-append #$output "/share/doc/gpu-switch-" #$version)))))
+      (home-page "https://github.com/0xbb/gpu-switch")
+      (supported-systems '("x86_64-linux"))      
+      (synopsis "GPU switcher for dual-GPU MacBook Pro models")
+      (description
+       "Switch between the integrated and dedicated GPU of dual-GPU MacBook Pro
+models for the next reboot.
+
+It aims to remove the need of booting into OS X and running gfxCardStatus
+v2.2.1 to switch to the integrated card.")
+      (license license:expat))))
-- 
2.34.0