Check if AMD GPU scaling is enabled to allow changing resolution by default

PowerControl/Helpers/AMD.cs

@@ -0,0 +1,44 @@
+using Microsoft.Win32;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace PowerControl.Helpers
+{
+    internal class AMD
+    {
+        // TODO: This CLSID is likely to change over time and be broken
+        // pnputil /enum-devices /class Display
+        const String GPUDriverKey = "SYSTEM\\CurrentControlSet\\Control\\Class\\{4d36e968-e325-11ce-bfc1-08002be10318}\\0000";
+        const String DriverDesc = "DriverDesc";
+        const String ExpectedDriverDesc = "AMD Custom GPU 0405";
+        const String GPUScaling = "GPUScaling00";
+
+        internal static bool IsGPUScalingEnabled()
+        {
+            try
+            {
+                var registry = Registry.LocalMachine.OpenSubKey(GPUDriverKey);
+                if (registry == null)
+                    return false;
+
+                var driverDesc = registry.GetValue(DriverDesc);
+                if (driverDesc is String && ((string)driverDesc) != ExpectedDriverDesc)
+                    return false;
+
+                var scalingBytes = registry.GetValue(GPUScaling);
+                if (scalingBytes is not byte[])
+                    return false;
+
+                var scaling = BitConverter.ToUInt32((byte[])scalingBytes);
+                return scaling == 1;
+            }
+            catch
+            {
+                return false;
+            }
+        }
+    }
+}

PowerControl/Helpers/WindowsSettingsBrightnessController.cs

@@ -11,16 +11,23 @@ namespace PowerControl.Helpers
     {
         public static int Get()
         {
-            using var mclass = new ManagementClass("WmiMonitorBrightness")
+            try
             {
-                Scope = new ManagementScope(@"\\.\root\wmi")
-            };
-            using var instances = mclass.GetInstances();
-            foreach (ManagementObject instance in instances)
-            {
-                return (byte)instance.GetPropertyValue("CurrentBrightness");
+                using var mclass = new ManagementClass("WmiMonitorBrightness")
+                {
+                    Scope = new ManagementScope(@"\\.\root\wmi")
+                };
+                using var instances = mclass.GetInstances();
+                foreach (ManagementObject instance in instances)
+                {
+                    return (byte)instance.GetPropertyValue("CurrentBrightness");
+                }
+                return -1;
+            }
+            catch
+            {
+                return -1;
             }
-            return -1;
         }
 
         public static int Get(double roundValue = 10.0)

PowerControl/MenuStack.cs

@@ -56,7 +56,7 @@ namespace PowerControl
                     Name = "Resolution",
                     ApplyDelay = 1000,
                     ResetValue = () => {
-                        if (!Settings.Default.EnableExperimentalFeatures)
+                        if (!AMD.IsGPUScalingEnabled() && !Settings.Default.EnableExperimentalFeatures)
                             return null;
                         return Helpers.PhysicalMonitorBrightnessController.GetAllResolutions().Last();
                     },
@@ -69,7 +69,7 @@ namespace PowerControl
                     },
                     CurrentValue = delegate()
                     {
-                        if (!Settings.Default.EnableExperimentalFeatures)
+                        if (!AMD.IsGPUScalingEnabled() && !Settings.Default.EnableExperimentalFeatures)
                             return null;
                         return Helpers.PhysicalMonitorBrightnessController.GetResolution();
                     },