Subject: [PATCH 2/2] services: Add speakersafetyd service.

From: Roman Scherer <[email-masked]>
Date: Fri, 14 Feb 2025 14:58:10 +0100

* gnu/services/sound.scm (speakersafetyd-service-type) New variable.
* doc/guix.texi: Document the speakersafetyd service.

Change-Id: Ib8fa19b056a2036019ae7c199d81e1139664e951
---
 doc/guix.texi          | 41 ++++++++++++++++++++++++++++
 gnu/services/sound.scm | 61 +++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 101 insertions(+), 1 deletion(-)

diff --git a/doc/guix.texi b/doc/guix.texi
index bd66adf326..3b82df5196 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -26575,6 +26575,47 @@ Sound Services
 
 @end defvar
 
+@subsubheading Speaker Safety Daemon System Service
+
+@uref{https://github.com/AsahiLinux/speakersafetyd, Speaker Safety
+Daemon} is a userspace daemon that implements an analogue of the Texas
+Instruments Smart Amp speaker protection model.  It can be used to
+protect the speakers on Apple Silicon devices.
+
+@defvar speakersafetyd-service-type
+This is the type for the @code{speakersafetyd} system service, whose
+value is a @command{speakersafetyd-configuration} record.
+
+@lisp
+(service speakersafetyd-service-type)
+@end lisp
+
+See below for details about @code{speakersafetyd-configuration}.
+@end defvar
+
+@deftp {Data Type} speakersafetyd-configuration
+Data type representing the configuration for @code{speakersafetyd-service}.
+
+@table @asis
+@item @code{blackbox-path} (default: @code{"/var/lib/speakersafetyd/blackbox"})
+The path to a directory to which "blackbox" files are written when the
+speakers are getting too hot.  The blackbox files contain audio and
+debug information which the developers of @code{speakersafetyd} might
+ask for when reporting bugs.
+
+@item @code{config-path} (default: @code{(file-append speakersafetyd "/share/speakersafetyd")})
+Path to the base directory as a G-expression (@pxref{G-Expressions})
+that contains the configuration files of the speaker models.
+
+@item @code{max-reduction} (default: @code{7})
+Maximum gain reduction before panicing, useful for debugging.
+
+@item @code{package} (default: @var{speakersafetyd})
+The Speaker Safety Daemon package to use.
+
+@end table
+@end deftp
+
 @node File Search Services
 @subsection File Search Services
 
diff --git a/gnu/services/sound.scm b/gnu/services/sound.scm
index 8ca7acd737..fb8a8d3d17 100644
--- a/gnu/services/sound.scm
+++ b/gnu/services/sound.scm
@@ -35,6 +35,7 @@ (define-module (gnu services sound)
   #:use-module (gnu packages audio)
   #:use-module (gnu packages linux)
   #:use-module (gnu packages pulseaudio)
+  #:use-module (gnu packages rust-apps)
   #:use-module (ice-9 match)
   #:use-module (srfi srfi-1)
   #:export (alsa-configuration
@@ -56,7 +57,15 @@ (define-module (gnu services sound)
             ladspa-configuration
             ladspa-configuration?
             ladspa-configuration-plugins
-            ladspa-service-type))
+            ladspa-service-type
+
+            speakersafetyd-configuration
+            speakersafetyd-configuration-blackbox-path
+            speakersafetyd-configuration-config-path
+            speakersafetyd-configuration-max-reduction
+            speakersafetyd-configuration-package
+            speakersafetyd-configuration?
+            speakersafetyd-service-type))
 
 ;;; Commentary:
 ;;;
@@ -263,4 +272,54 @@ (define ladspa-service-type
    (default-value (ladspa-configuration))
    (description "Configure LADSPA plugins.")))
 
+
+;;;
+;;; Speaker Safety Daemon
+;;;
+
+(define-record-type* <speakersafetyd-configuration>
+  speakersafetyd-configuration
+  make-speakersafetyd-configuration
+  speakersafetyd-configuration?
+  (blackbox-path speakersafetyd-configuration-blackbox-path
+                 (default "/var/lib/speakersafetyd/blackbox"))
+  (config-path speakersafetyd-configuration-config-path
+               (default (file-append speakersafetyd "/share/speakersafetyd")))
+  (max-reduction speakersafetyd-configuration-max-reduction
+                 (default 7))
+  (package speakersafetyd-configuration-package
+           (default speakersafetyd)))
+
+(define (speakersafetyd-shepherd-service config)
+  (let ((blackbox-path (speakersafetyd-configuration-blackbox-path config))
+        (config-path (speakersafetyd-configuration-config-path config))
+        (max-reduction (speakersafetyd-configuration-max-reduction config))
+        (package (speakersafetyd-configuration-package config)))
+    (shepherd-service
+     (documentation "Speaker saftey daemon")
+     (provision '(speakersafetyd))
+     (requirement '(udev))
+     (start #~(make-forkexec-constructor
+               (list #$(file-append package "/bin/speakersafetyd")
+                     "--config-path" #$config-path
+                     "--blackbox-path" #$blackbox-path
+                     "--max-reduction" (number->string #$max-reduction))))
+     (stop #~(make-kill-destructor)))))
+
+(define speakersafetyd-service-type
+  (service-type
+   (name 'speakersafetyd)
+   (description "Speaker Saftey Daemon")
+   (extensions
+    (list (service-extension
+           profile-service-type
+           (compose list speakersafetyd-configuration-package))
+          (service-extension
+           shepherd-root-service-type
+           (compose list speakersafetyd-shepherd-service))
+          (service-extension
+           udev-service-type
+           (compose list speakersafetyd-configuration-package))))
+   (default-value (speakersafetyd-configuration))))
+
 ;;; sound.scm ends here
-- 
2.48.1