Subject: [PATCH v3 2/2] services: Add speakersafetyd service.

From: Roman Scherer <[email-masked]>
Date: Sat, 15 Feb 2025 10:24:35 +0100

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

Change-Id: Ib8fa19b056a2036019ae7c199d81e1139664e951
---
 doc/guix.texi          | 42 +++++++++++++++++++++++++++
 gnu/services/sound.scm | 65 +++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 106 insertions(+), 1 deletion(-)

diff --git a/doc/guix.texi b/doc/guix.texi
index bd66adf326..ec5c7ab5cf 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -26575,6 +26575,48 @@ Sound Services
 
 @end defvar
 
+@subsubheading Speaker Safety Daemon System Service
+
+@uref{https://github.com/AsahiLinux/speakersafetyd, Speaker Safety
+Daemon} is a user-space 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
+Available @code{speakersafetyd-configuration} fields are:
+
+@table @asis
+@item @code{blackbox-directory} (default: @code{"/var/lib/speakersafetyd/blackbox"}) (type: string)
+The 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{configuration-directory} (type: file-like)
+The base directory as a G-expression (@pxref{G-Expressions}) that
+contains the configuration files of the speaker models.
+
+@item @code{maximum-gain-reduction} (default: @code{7}) (type: integer)
+Maximum gain reduction before panicing, useful for debugging.
+
+@item @code{speakersafetyd} (default: @code{speakersafetyd}) (type: file-like)
+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..bf7d3cc6b0 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-directory
+            speakersafetyd-configuration-configuration-directory
+            speakersafetyd-configuration-maximum-gain-reduction
+            speakersafetyd-configuration-speakersafetyd
+            speakersafetyd-configuration?
+            speakersafetyd-service-type))
 
 ;;; Commentary:
 ;;;
@@ -263,4 +272,58 @@ (define ladspa-service-type
    (default-value (ladspa-configuration))
    (description "Configure LADSPA plugins.")))
 
+
+;;;
+;;; Speaker Safety Daemon
+;;;
+
+(define-configuration/no-serialization speakersafetyd-configuration
+  (blackbox-directory
+   (string "/var/lib/speakersafetyd/blackbox")
+   "The 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.")
+  (configuration-directory
+   (file-like (file-append speakersafetyd "/share/speakersafetyd"))
+   "The base directory as a G-expression (@pxref{G-Expressions}) that contains
+the configuration files of the speaker models.")
+  (maximum-gain-reduction
+   (integer 7)
+   "Maximum gain reduction before panicing, useful for debugging.")
+  (speakersafetyd
+   (file-like speakersafetyd)
+   "The Speaker Safety Daemon package to use."))
+
+(define speakersafetyd-shepherd-service
+  (match-record-lambda <speakersafetyd-configuration>
+      (blackbox-directory configuration-directory maximum-gain-reduction speakersafetyd)
+    (shepherd-service
+     (documentation "Run the speaker safety daemon")
+     (provision '(speakersafetyd))
+     (requirement '(udev))
+     (start #~(make-forkexec-constructor
+               (list #$(file-append speakersafetyd "/bin/speakersafetyd")
+                     "--config-path" #$configuration-directory
+                     "--blackbox-path" #$blackbox-directory
+                     "--max-reduction" (number->string #$maximum-gain-reduction))))
+     (stop #~(make-kill-destructor)))))
+
+(define speakersafetyd-service-type
+  (service-type
+   (name 'speakersafetyd)
+   (description "Run @command{speakersafetyd}, a user space 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.")
+   (extensions
+    (list (service-extension
+           shepherd-root-service-type
+           (compose list speakersafetyd-shepherd-service))
+          (service-extension
+           udev-service-type
+           (compose list speakersafetyd-configuration-speakersafetyd))
+          (service-extension
+           profile-service-type
+           (compose list speakersafetyd-configuration-speakersafetyd))))
+   (default-value (speakersafetyd-configuration))))
+
 ;;; sound.scm ends here
-- 
2.48.1