Address review feedback on concurrency and DDC fixes

- Drop DispatchQueue.main.sync around CGSetDisplayTransferByTable in the smooth-brightness loop. CoreGraphics does not require the main thread here, and hopping per gamma step (~200 iterations) both stalled the animation and contended with main-thread UI work. - Address the global preferences domain via UserDefaults.globalDomain instead of the literal ".GlobalPreferences", which is a filename and not a CFPreferences application ID. The old form returned nil, so the volume-changed beep silently never played. - Restore the original DDC attempt count. The retry cap regressed the default from 5 attempts to 4 (and minimal polling from 2 to 1); it is now min(attempts + 1, 30), preserving prior behaviour under the cap. - Migrate the login-item status read in MainPrefsViewController to SMAppService.loginItem(_:).status on macOS 13+. The writer had moved to SMAppService while the reader still used SMCopyAllJobDictionaries, so the Start at login checkbox showed stale state. - Track DDC write success across every attempted control code rather than letting the last iteration win, so writeDDCLastSavedValue and isTouched are persisted only when all attempted writes actually succeeded. kIOMainPortDefault is intentionally changed only in Arm64DDC, where it is guarded by an availability check. The remaining call sites stay on kIOMasterPortDefault because the project's deployment target predates macOS 12.
MyronKoch · May 29, 2026 · Sep 21, 2026 · Sep 21, 2026 · 5afd2153ca0ab1885dff2123dc674e29c94f720b
commit 5afd2153ca0ab1885dff2123dc674e29c94f720b
diff --git a/MonitorControl/Model/Display.swift b/MonitorControl/Model/Display.swift
@@ -238,9 +238,7 @@ class Display: Equatable {
             let gammaTableRed = self.defaultGammaTableRed.map { $0 * transientValue }
             let gammaTableGreen = self.defaultGammaTableGreen.map { $0 * transientValue }
             let gammaTableBlue = self.defaultGammaTableBlue.map { $0 * transientValue }
-            DispatchQueue.main.sync {
-              CGSetDisplayTransferByTable(self.identifier, self.defaultGammaTableSampleCount, gammaTableRed, gammaTableGreen, gammaTableBlue)
-            }
+            CGSetDisplayTransferByTable(self.identifier, self.defaultGammaTableSampleCount, gammaTableRed, gammaTableGreen, gammaTableBlue)
           }
           Thread.sleep(forTimeInterval: 0.001) // Let's make things quick if not performed in the background
         }

diff --git a/MonitorControl/Model/OtherDisplay.swift b/MonitorControl/Model/OtherDisplay.swift
@@ -401,24 +401,25 @@ class OtherDisplay: Display {
       controlCodes.append(command.rawValue)
     }
     var writeAttempted = false
-    var writeSucceeded = true
+    var allSucceeded = true
     for controlCode in controlCodes {
       if Arm64DDC.isArm64 {
         if self.arm64ddc {
           writeAttempted = true
-          writeSucceeded = Arm64DDC.write(service: self.arm64avService, command: controlCode, value: value)
+          if !Arm64DDC.write(service: self.arm64avService, command: controlCode, value: value) {
+            allSucceeded = false
+          }
         }
       } else {
         if self.ddc != nil {
           writeAttempted = true
-          writeSucceeded = self.ddc?.write(command: controlCode, value: value, errorRecoveryWaitTime: 2000) ?? false
+          if !(self.ddc?.write(command: controlCode, value: value, errorRecoveryWaitTime: 2000) ?? false) {
+            allSucceeded = false
+          }
         }
       }
-      if writeAttempted, !writeSucceeded {
-        break
-      }
     }
-    if writeAttempted, writeSucceeded {
+    if writeAttempted, allSucceeded {
       self.writeDDCQueue.async(flags: .barrier) {
         self.writeDDCLastSavedValue[command] = value
         self.savePref(true, key: PrefKey.isTouched, for: command)

diff --git a/MonitorControl/Support/AppDelegate.swift b/MonitorControl/Support/AppDelegate.swift
@@ -360,7 +360,7 @@ class AppDelegate: NSObject, NSApplicationDelegate {
   }
 
   func getSystemSettings() -> [String: Any]? {
-    UserDefaults.standard.persistentDomain(forName: ".GlobalPreferences")
+    UserDefaults.standard.persistentDomain(forName: UserDefaults.globalDomain)
   }
 
   func macOS10() -> Bool {

diff --git a/MonitorControl/Support/Arm64DDC.swift b/MonitorControl/Support/Arm64DDC.swift
@@ -100,7 +100,7 @@ class Arm64DDC: NSObject {
     }
     var packet: [UInt8] = [UInt8(0x80 | (send.count + 1)), UInt8(send.count)] + send + [0] // Note: the last byte is the place of the checksum, see next line!
     packet[packet.count - 1] = self.checksum(chk: send.count == 1 ? ARM64_DDC_7BIT_ADDRESS << 1 : ARM64_DDC_7BIT_ADDRESS << 1 ^ dataAddress, data: &packet, start: 0, end: packet.count - 2)
-    let attempts = max(1, Int(min(numOfRetryAttemps ?? 4, UInt8(30))))
+    let attempts = min(Int(numOfRetryAttemps ?? 4) + 1, 30)
     for _ in 0 ..< attempts {
       for _ in 1 ... max((numOfWriteCycles ?? 2) + 0, 1) {
         usleep(writeSleepTime ?? 10000)

diff --git a/MonitorControl/View Controllers/Preferences/MainPrefsViewController.swift b/MonitorControl/View Controllers/Preferences/MainPrefsViewController.swift
@@ -52,8 +52,13 @@ class MainPrefsViewController: NSViewController, SettingsPane {
 
   @available(macOS, deprecated: 10.10)
   func populateSettings() {
-    // This is marked as deprectated but according to the function header it still does not have a replacement as of macOS 12 Monterey and is valid to use.
-    let startAtLogin = (SMCopyAllJobDictionaries(kSMDomainUserLaunchd).takeRetainedValue() as? [[String: AnyObject]])?.first { $0["Label"] as? String == "\(Bundle.main.bundleIdentifier!)Helper" }?["OnDemand"] as? Bool ?? false
+    let startAtLogin: Bool
+    let helperID = "\(Bundle.main.bundleIdentifier!)Helper"
+    if #available(macOS 13.0, *) {
+      startAtLogin = SMAppService.loginItem(identifier: helperID).status == .enabled
+    } else {
+      startAtLogin = (SMCopyAllJobDictionaries(kSMDomainUserLaunchd).takeRetainedValue() as? [[String: AnyObject]])?.first { $0["Label"] as? String == helperID }?["OnDemand"] as? Bool ?? false
+    }
     self.startAtLogin.state = startAtLogin ? .on : .off
     self.automaticUpdateCheck.state = prefs.bool(forKey: PrefKey.SUEnableAutomaticChecks.rawValue) ? .on : .off
     self.combinedBrightness.state = prefs.bool(forKey: PrefKey.disableCombinedBrightness.rawValue) ? .off : .on