uvc: log control responses

server/src/bin/lesavka-uvc.rs

@@ -411,6 +411,14 @@ fn handle_setup(
     );
     match payload {
         Some(bytes) => {
+            if debug {
+                eprintln!(
+                    "[lesavka-uvc] send IN response rq=0x{:02x} sel={} len={}",
+                    req.b_request,
+                    selector,
+                    bytes.len()
+                );
+            }
             let _ = send_response(fd, uvc_send_response, &bytes);
         }
         None => {
@@ -517,6 +525,12 @@ fn handle_data(
                 );
             }
         }
+        if debug {
+            eprintln!(
+                "[lesavka-uvc] send SET_CUR status sel={} len=0",
+                p.selector
+            );
+        }
         let _ = send_response(fd, uvc_send_response, &[]);
     }
 }