From 46e25cbc5ff62e24f86574d7ae5d872aa0c2595d Mon Sep 17 00:00:00 2001
From: Gerhard de Clercq <11624490+Gerharddc@users.noreply.github.com>
Date: Tue, 13 May 2025 15:09:53 +0200
Subject: [PATCH] [embassy-usb-dfu] correct comment about composite devices

---
 embassy-usb-dfu/src/application.rs                |  5 +++--
 embassy-usb-dfu/src/dfu.rs                        |  5 +++--
 examples/boot/application/stm32wb-dfu/src/main.rs | 10 ++++------
 examples/boot/bootloader/stm32wb-dfu/src/main.rs  | 10 ++++------
 4 files changed, 14 insertions(+), 16 deletions(-)

diff --git a/embassy-usb-dfu/src/application.rs b/embassy-usb-dfu/src/application.rs
index 52a7ca951..2646d100d 100644
--- a/embassy-usb-dfu/src/application.rs
+++ b/embassy-usb-dfu/src/application.rs
@@ -137,8 +137,9 @@ pub fn usb_dfu<'d, D: Driver<'d>, MARK: DfuMarker, RST: Reset>(
         // We add MSOS headers so that the device automatically gets assigned the WinUSB driver on Windows.
         // Otherwise users need to do this manually using a tool like Zadig.
         //
-        // Adding them here on the function level appears to only work for compositive devices though.
-        // For non-composite devices they should be placed on the device level instead.
+        // Adding them here on the function level appears to only be needed for compositive devices.
+        // In addition to being on the function level, they should also be added to the device level.
+        //
         func.msos_feature(msos::CompatibleIdFeatureDescriptor::new("WINUSB", ""));
         func.msos_feature(msos::RegistryPropertyFeatureDescriptor::new(
             "DeviceInterfaceGUIDs",
diff --git a/embassy-usb-dfu/src/dfu.rs b/embassy-usb-dfu/src/dfu.rs
index 83feacaf8..43a35637d 100644
--- a/embassy-usb-dfu/src/dfu.rs
+++ b/embassy-usb-dfu/src/dfu.rs
@@ -193,8 +193,9 @@ pub fn usb_dfu<'d, D: Driver<'d>, DFU: NorFlash, STATE: NorFlash, RST: Reset, co
         // We add MSOS headers so that the device automatically gets assigned the WinUSB driver on Windows.
         // Otherwise users need to do this manually using a tool like Zadig.
         //
-        // Adding them here on the function level appears to only work for compositive devices though.
-        // For non-composite devices they should be placed on the device level instead.
+        // Adding them here on the function level appears to only be needed for compositive devices.
+        // In addition to being on the function level, they should also be added to the device level.
+        //
         func.msos_feature(msos::CompatibleIdFeatureDescriptor::new("WINUSB", ""));
         func.msos_feature(msos::RegistryPropertyFeatureDescriptor::new(
             "DeviceInterfaceGUIDs",
diff --git a/examples/boot/application/stm32wb-dfu/src/main.rs b/examples/boot/application/stm32wb-dfu/src/main.rs
index 68e9bc3f6..6236dfe52 100644
--- a/examples/boot/application/stm32wb-dfu/src/main.rs
+++ b/examples/boot/application/stm32wb-dfu/src/main.rs
@@ -59,13 +59,11 @@ async fn main(_spawner: Spawner) {
 
     // We add MSOS headers so that the device automatically gets assigned the WinUSB driver on Windows.
     // Otherwise users need to do this manually using a tool like Zadig.
-    builder.msos_descriptor(msos::windows_version::WIN8_1, 2);
-
-    // In the case of non-composite devices, it seems that feature headers need to be on the device level.
-    // (As is implemented here)
     //
-    // For composite devices however, they should be on the function level instead.
-    // (This is achieved by passing a GUID to the "usb_dfu" function)
+    // It seems these always need to be at added at the device level for this to work and for
+    // composite devices they also need to be added on the function level (as shown later).
+    //
+    builder.msos_descriptor(msos::windows_version::WIN8_1, 2);
     builder.msos_feature(msos::CompatibleIdFeatureDescriptor::new("WINUSB", ""));
     builder.msos_feature(msos::RegistryPropertyFeatureDescriptor::new(
         "DeviceInterfaceGUIDs",
diff --git a/examples/boot/bootloader/stm32wb-dfu/src/main.rs b/examples/boot/bootloader/stm32wb-dfu/src/main.rs
index 2cd7f859d..8cfd4daa7 100644
--- a/examples/boot/bootloader/stm32wb-dfu/src/main.rs
+++ b/examples/boot/bootloader/stm32wb-dfu/src/main.rs
@@ -67,13 +67,11 @@ fn main() -> ! {
 
         // We add MSOS headers so that the device automatically gets assigned the WinUSB driver on Windows.
         // Otherwise users need to do this manually using a tool like Zadig.
-        builder.msos_descriptor(msos::windows_version::WIN8_1, 2);
-
-        // In the case of non-composite devices, it seems that feature headers need to be on the device level.
-        // (As is implemented here)
         //
-        // For composite devices however, they should be on the function level instead.
-        // (This is achieved by passing a GUID to the "usb_dfu" function)
+        // It seems these always need to be at added at the device level for this to work and for
+        // composite devices they also need to be added on the function level (as shown later).
+        //
+        builder.msos_descriptor(msos::windows_version::WIN8_1, 2);
         builder.msos_feature(msos::CompatibleIdFeatureDescriptor::new("WINUSB", ""));
         builder.msos_feature(msos::RegistryPropertyFeatureDescriptor::new(
             "DeviceInterfaceGUIDs",