Kernel driver and EC access code improvements

- Fix CreateFile() errors potentially not getting caught

- Attempt to connect to an existing installed WinRing0 driver before attempting an install ourselves

- Only uninstall the WinRing0 driver if it's not being used by any other programs

- Only attempt to read/write EC if the EC driver connection is open

MSIFanControl.ECAccess/Driver.cs

@@ -81,6 +81,7 @@ public bool Install()
         {
             ErrorCode = 0;
 
+            // Make sure the file we're trying to install actually exists:
             try
             {
                 string fullPath = Path.GetFullPath(DriverPath);
@@ -91,7 +92,6 @@ public bool Install()
                 return false;
             }
 
-            // Otherwise, we need to install the service ourselves.
             // Try to open the Service Control Manager:
             IntPtr hSCM = AdvApi32.OpenSCManager(null, null, AdvApi32.SCMAccess.All);
             if (hSCM == IntPtr.Zero)
@@ -238,21 +238,24 @@ public bool Open()
                     FileAttributes.Normal,
                     IntPtr.Zero);
 
-                if (hDevice != IntPtr.Zero)
+                // Apparently CreateFileW() can return -1 instead of 0 for some reason
+                if (hDevice == IntPtr.Zero || hDevice == new IntPtr(-1))
                 {
-                    Status |= DriverStatus.Open;
-                    return true;
+                    ErrorCode = Marshal.GetLastWin32Error();
+                    return false;
                 }
-                ErrorCode = Marshal.GetLastWin32Error();
-                return false;
+
+
+                Status |= DriverStatus.Open;
+                return true;
             }
             return true;
         }
 
         /// <summary>
         /// Closes the connection to the device driver, if open.
         /// </summary>
-        private void Close()
+        public void Close()
         {
             if (hDevice != IntPtr.Zero)
             {

MSIFanControl.ECAccess/EC.cs

@@ -96,7 +96,21 @@ public EC()
         /// </returns>
         public bool LoadDriver()
         {
-            return _Driver.Install() && _Driver.Open();
+            // Attempt to open an already installed WinRing0 driver first
+            if (_Driver.Open())
+            {
+                return true;
+            }
+
+            // If opening the driver fails, uninstall (if installed) and reinstall it
+            _Driver.Uninstall();
+            if (!_Driver.Install())
+            {
+                _Driver.Uninstall();
+                return false;
+            }
+
+            return _Driver.Open();
         }
 
         /// <summary>
@@ -108,7 +122,17 @@ public bool LoadDriver()
         /// </remarks>
         public void UnloadDriver()
         {
-            _Driver.Uninstall();
+            if (GetRefCount() <= 1)
+            {
+                // only uninstall the driver if we're the last program using it
+                // (Driver.Uninstall() calles Driver.Close() internally)
+                _Driver.Uninstall();
+            }
+            else
+            {
+                // otherwise, just close the handle to the driver
+                _Driver.Close();
+            }
         }
 
         /// <summary>
@@ -119,11 +143,16 @@ public void UnloadDriver()
         public bool ReadByte(byte register, out byte value)
         {
             value = 0;
-            for (int i = 0; i < RW_MAX_RETRIES; i++)
+
+            // only attempt to read EC if driver connection has been opened
+            if ((_Driver.Status & DriverStatus.Open) == DriverStatus.Open)
             {
-                if (TryReadByte(register, out value))
+                for (int i = 0; i < RW_MAX_RETRIES; i++)
                 {
-                    return true;
+                    if (TryReadByte(register, out value))
+                    {
+                        return true;
+                    }
                 }
             }
             return false;
@@ -136,13 +165,18 @@ public bool ReadByte(byte register, out byte value)
         /// <param name="value">The value to write at the register.</param>
         public bool WriteByte(byte register, byte value)
         {
-            for (int i = 0; i < RW_MAX_RETRIES; i++)
+            // only attempt to write EC if driver connection has been opened
+            if ((_Driver.Status & DriverStatus.Open) == DriverStatus.Open)
             {
-                if (TryWriteByte(register, value))
+                for (int i = 0; i < RW_MAX_RETRIES; i++)
                 {
-                    return true;
+                    if (TryWriteByte(register, value))
+                    {
+                        return true;
+                    }
                 }
             }
+
             return false;
         }
 
@@ -158,13 +192,19 @@ public bool WriteByte(byte register, byte value)
         public bool ReadWord(byte register, out ushort value, bool bigEndian = false)
         {
             value = 0;
-            for (int i = 0; i < RW_MAX_RETRIES; i++)
+
+            // only attempt to read EC if driver connection has been opened
+            if ((_Driver.Status & DriverStatus.Open) == DriverStatus.Open)
             {
-                if (TryReadWord(register, bigEndian, out value))
+                for (int i = 0; i < RW_MAX_RETRIES; i++)
                 {
-                    return true;
+                    if (TryReadWord(register, bigEndian, out value))
+                    {
+                        return true;
+                    }
                 }
             }
+
             return false;
         }
 
@@ -179,13 +219,18 @@ public bool ReadWord(byte register, out ushort value, bool bigEndian = false)
         /// </param>
         public bool WriteWord(byte register, ushort value, bool bigEndian = false)
         {
-            for (int i = 0; i < RW_MAX_RETRIES; i++)
+            // only attempt to write EC if driver connection has been opened
+            if ((_Driver.Status & DriverStatus.Open) == DriverStatus.Open)
             {
-                if (TryWriteWord(register, value, bigEndian))
+                for (int i = 0; i < RW_MAX_RETRIES; i++)
                 {
-                    return true;
+                    if (TryWriteWord(register, value, bigEndian))
+                    {
+                        return true;
+                    }
                 }
             }
+
             return false;
         }
 
@@ -337,6 +382,12 @@ private bool WriteIOPort(ushort port, byte value)
             return _Driver.IOControl((uint)Ring0Control.WriteIOPortByte, input, null);
         }
 
+        private uint GetRefCount()
+        {
+            uint refCount = 0;
+            return _Driver.IOControl((uint)Ring0Control.GetRefCount, ref refCount, out refCount) ? refCount : 0;
+        }
+
         /// <summary>
         /// Gets the status of the WinRing0 driver.
         /// </summary>

MSIFanControl.ECAccess/MSIFanControl.ECAccess.csproj

@@ -64,6 +64,12 @@
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
   </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\MSIFanControl.Logging\MSIFanControl.Logs.csproj">
+      <Project>{5c611048-093e-48ac-b525-5c24817081bb}</Project>
+      <Name>MSIFanControl.Logs</Name>
+    </ProjectReference>
+  </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <PropertyGroup>
     <PostBuildEvent>