From 4b3b0095a08b5d423153f6c44d01b12d696c1a78 Mon Sep 17 00:00:00 2001
From: rootiest <chris@rootiest.com>
Date: Fri, 10 Apr 2026 15:57:16 -0400
Subject: [PATCH] feat: add --no-volume, --no-brightness, --no-active-app
 disable flags

Each flag prevents the corresponding monitor thread from being spawned,
saving the polling overhead and any associated system calls for users
who don't need that feature:

  --no-volume      skip pactl polling (CMD_VOLUME)
  --no-brightness  skip /sys/class/backlight polling (CMD_BRIGHTNESS)
  --no-active-app  skip the active-app monitor (CMD_ACTIVE_APP, stub today)

A disabled monitor logs a single info message at startup so the user
knows it was intentionally skipped rather than silently missing.
---
 src/main.rs | 47 +++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 39 insertions(+), 8 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index 40a0ea2..706f3df 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -16,11 +16,14 @@
 //! # Usage
 //!
 //! ```
-//! qmk-host            # info-level output (connections, value changes)
-//! qmk-host -v         # debug-level: log every packet cmd/src/flags
-//! qmk-host -vv        # trace-level: full 32-byte hex dump of every packet
-//! qmk-host -q         # quiet: errors only
-//! RUST_LOG=debug qmk-host   # env var still works as an override
+//! qmk-host                          # info-level output (connections, value changes)
+//! qmk-host -v                       # debug: log every packet cmd/src/flags
+//! qmk-host -vv                      # trace: full 32-byte hex dump of every packet
+//! qmk-host -q                       # quiet: errors only
+//! qmk-host --no-volume              # skip pactl polling
+//! qmk-host --no-brightness          # skip /sys/class/backlight polling
+//! qmk-host --no-active-app          # skip active-app monitor (stub today)
+//! RUST_LOG=debug qmk-host           # env var still works as an override
 //! ```
 //!
 //! # Permissions
@@ -75,6 +78,28 @@ struct Args {
     /// Suppress all output except errors.
     #[arg(short, long)]
     quiet: bool,
+
+    /// Disable system volume monitoring.
+    ///
+    /// When set, no CMD_VOLUME packets are sent to keyboards and the pactl
+    /// polling thread is never started.
+    #[arg(long)]
+    no_volume: bool,
+
+    /// Disable screen brightness monitoring.
+    ///
+    /// When set, no CMD_BRIGHTNESS packets are sent to keyboards and the
+    /// /sys/class/backlight polling thread is never started.
+    #[arg(long)]
+    no_brightness: bool,
+
+    /// Disable active-application monitoring.
+    ///
+    /// When set, the active-app monitor thread is never started.  This flag
+    /// is a no-op today (the monitor is a stub) but is provided so it can be
+    /// toggled off once the feature is implemented.
+    #[arg(long)]
+    no_active_app: bool,
 }
 
 impl Args {
@@ -178,7 +203,9 @@ fn main() -> Result<()> {
     }
 
     // Volume monitor: polls pactl, pushes CMD_VOLUME to all keyboards.
-    {
+    if args.no_volume {
+        info!("Volume monitoring disabled (--no-volume)");
+    } else {
         let kbds = keyboards.clone();
         thread::Builder::new()
             .name("volume-monitor".into())
@@ -187,7 +214,9 @@ fn main() -> Result<()> {
     }
 
     // Brightness monitor: polls /sys, pushes CMD_BRIGHTNESS to all keyboards.
-    {
+    if args.no_brightness {
+        info!("Brightness monitoring disabled (--no-brightness)");
+    } else {
         let kbds = keyboards.clone();
         thread::Builder::new()
             .name("brightness-monitor".into())
@@ -196,7 +225,9 @@ fn main() -> Result<()> {
     }
 
     // Active-app monitor: stub, does nothing until implemented.
-    {
+    if args.no_active_app {
+        info!("Active-app monitoring disabled (--no-active-app)");
+    } else {
         let kbds = keyboards.clone();
         thread::Builder::new()
             .name("app-monitor".into())