From 3de19d259544e9479ae951c6e68ad5c16ae63b40 Mon Sep 17 00:00:00 2001
From: Tim Besard <tim.besard@gmail.com>
Date: Thu, 2 Jul 2026 18:04:58 +0200
Subject: [PATCH] fix(ddc): send VCP writes twice

Do not stop after the first successful I2C write;
MonitorControl's Arm64 DDC path also runs the configured write cycles.
---
 FineTune/Audio/DDC/DDCService.swift | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/FineTune/Audio/DDC/DDCService.swift b/FineTune/Audio/DDC/DDCService.swift
index 524d88b3..55aaa4d5 100644
--- a/FineTune/Audio/DDC/DDCService.swift
+++ b/FineTune/Audio/DDC/DDCService.swift
@@ -137,16 +137,18 @@ final class DDCService: @unchecked Sendable {
     }
 
     /// Writes a DDC packet without reading a response.
+    ///
+    /// Send all write cycles; some displays only apply the second write.
     private func i2cWrite(packet: [UInt8]) throws {
+        var lastResult: IOReturn = kIOReturnError
         for _ in 0..<numWriteCycles {
             usleep(writeSleepTime)
-            let result = packet.withUnsafeBufferPointer { buf in
+            lastResult = packet.withUnsafeBufferPointer { buf in
                 IOAVServiceLoader.writeI2C(service: service, chipAddress: chipAddress,
                                            dataAddress: writeAddress, buffer: buf.baseAddress!, size: UInt32(buf.count))
             }
-            if result == kIOReturnSuccess { return }
         }
-        throw DDCError.writeFailed(kIOReturnError)
+        guard lastResult == kIOReturnSuccess else { throw DDCError.writeFailed(lastResult) }
     }
 
     // MARK: - VCP Commands