feat(otg): 增加 libcomposite 自动加载兜底

src/otg/configfs.rs

@@ -3,6 +3,7 @@
 use std::fs::{self, File, OpenOptions};
 use std::io::Write;
 use std::path::Path;
+use std::process::Command;
 
 use crate::error::{AppError, Result};
 
@@ -29,6 +30,42 @@ pub fn is_configfs_available() -> bool {
     Path::new(CONFIGFS_PATH).exists()
 }
 
+/// Ensure libcomposite support is available for USB gadget operations.
+///
+/// This is a best-effort runtime fallback for systems where `libcomposite`
+/// is built as a module and not loaded yet. It does not try to mount configfs;
+/// mounting remains an explicit system responsibility.
+pub fn ensure_libcomposite_loaded() -> Result<()> {
+    if is_configfs_available() {
+        return Ok(());
+    }
+
+    if !Path::new("/sys/module/libcomposite").exists() {
+        let status = Command::new("modprobe")
+            .arg("libcomposite")
+            .status()
+            .map_err(|e| {
+                AppError::Internal(format!("Failed to run modprobe libcomposite: {}", e))
+            })?;
+
+        if !status.success() {
+            return Err(AppError::Internal(format!(
+                "modprobe libcomposite failed with status {}",
+                status
+            )));
+        }
+    }
+
+    if is_configfs_available() {
+        Ok(())
+    } else {
+        Err(AppError::Internal(
+            "libcomposite is not available after modprobe; check configfs mount and kernel support"
+                .to_string(),
+        ))
+    }
+}
+
 /// Find available UDC (USB Device Controller)
 pub fn find_udc() -> Option<String> {
     let udc_path = Path::new("/sys/class/udc");

src/otg/service.rs

@@ -397,6 +397,10 @@ impl OtgService {
             return Ok(());
         }
 
+        if let Err(e) = super::configfs::ensure_libcomposite_loaded() {
+            warn!("Failed to ensure libcomposite is available: {}", e);
+        }
+
         // Check if OTG is available
         if !Self::is_available() {
             let error = "OTG not available: ConfigFS not mounted or no UDC found".to_string();