diff --git a/examples/device/cdc_msc_hid/ses/samd21/samd21.emProject b/examples/device/cdc_msc_hid/ses/samd21/samd21.emProject
index d61b82cfa..fbb8841b7 100644
--- a/examples/device/cdc_msc_hid/ses/samd21/samd21.emProject
+++ b/examples/device/cdc_msc_hid/ses/samd21/samd21.emProject
@@ -22,6 +22,7 @@
       c_user_include_directories="../../src;$(rootDir)/hw/cmsis/Include;$(rootDir)/hw;$(rootDir)/src;$(asf4Dir);$(asf4Dir)/include;$(asf4Dir)/config;$(asf4Dir)/hri;$(asf4Dir)/hal/include;$(asf4Dir)/hal/utils/include;$(asf4Dir)/hpl/port;$(asf4Dir)/hpl/gclk;$(asf4Dir)/hpl/pm"
       debug_register_definition_file="ATSAMD21G18A_Registers.xml"
       debug_target_connection="J-Link"
+      gcc_enable_all_warnings="Yes"
       gcc_entry_point="Reset_Handler"
       link_use_linker_script_file="No"
       linker_memory_map_file="$(ProjectDir)/ATSAMD21G18A_MemoryMap.xml"
diff --git a/src/common/tusb_fifo.h b/src/common/tusb_fifo.h
index 61d92b602..e88c2ac6d 100644
--- a/src/common/tusb_fifo.h
+++ b/src/common/tusb_fifo.h
@@ -67,13 +67,12 @@ typedef struct
            uint8_t* buffer    ; ///< buffer pointer
            uint16_t depth     ; ///< max items
            uint16_t item_size ; ///< size of each item
+           bool overwritable  ;
 
   volatile uint16_t count     ; ///< number of items in queue
   volatile uint16_t wr_idx    ; ///< write pointer
   volatile uint16_t rd_idx    ; ///< read pointer
 
-           bool overwritable  ;
-
 #if CFG_FIFO_MUTEX
   tu_fifo_mutex_t mutex;
 #endif
diff --git a/src/device/usbd.c b/src/device/usbd.c
index ddb63cebb..206b663c0 100644
--- a/src/device/usbd.c
+++ b/src/device/usbd.c
@@ -161,8 +161,9 @@ enum { USBD_CLASS_DRIVER_COUNT = sizeof(usbd_class_drivers) / sizeof(usbd_class_
 //--------------------------------------------------------------------+
 OSAL_TASK_DEF(_usbd_task_def, "usbd", usbd_task, CFG_TUD_TASK_PRIO, CFG_TUD_TASK_STACK_SZ);
 
-/*------------- event queue -------------*/
-OSAL_QUEUE_DEF(_usbd_qdef, CFG_TUD_TASK_QUEUE_SZ, dcd_event_t);
+// Event queue
+// role device/host is used by OS NONE for mutex (disable usb isr) only
+OSAL_QUEUE_DEF(OPT_MODE_DEVICE, _usbd_qdef, CFG_TUD_TASK_QUEUE_SZ, dcd_event_t);
 static osal_queue_t _usbd_q;
 
 //--------------------------------------------------------------------+
@@ -200,15 +201,8 @@ tusb_error_t usbd_init (void)
   for (uint8_t i = 0; i < USBD_CLASS_DRIVER_COUNT; i++) usbd_class_drivers[i].init();
 
   // Init device controller driver
-  #if (CFG_TUSB_RHPORT0_MODE & OPT_MODE_DEVICE)
-  dcd_init(0);
-  dcd_int_enable(0);
-  #endif
-
-  #if (CFG_TUSB_RHPORT1_MODE & OPT_MODE_DEVICE)
-  dcd_init(1);
-  dcd_int_enable(1);
-  #endif
+  dcd_init(TUD_OPT_RHPORT);
+  dcd_int_enable(TUD_OPT_RHPORT);
 
   return TUSB_ERROR_NONE;
 }
@@ -268,14 +262,14 @@ static void usbd_task_body(void)
       break;
 
       case DCD_EVENT_BUS_RESET:
-        // note: if task is too slow, we could clear the event of the new attached
         usbd_reset(event.rhport);
+        // TODO remove since if task is too slow, we could clear the event of the new attached
         osal_queue_reset(_usbd_q);
       break;
 
       case DCD_EVENT_UNPLUGGED:
-        // note: if task is too slow, we could clear the event of the new attached
         usbd_reset(event.rhport);
+        // TODO remove since if task is too slow, we could clear the event of the new attached
         osal_queue_reset(_usbd_q);
 
         tud_umount_cb();    // invoke callback
@@ -587,6 +581,11 @@ void dcd_event_handler(dcd_event_t const * event, bool in_isr)
       TU_ASSERT(event->xfer_complete.result == XFER_RESULT_SUCCESS,);
     break;
 
+    // Not an DCD event, just a convenient way to defer ISR function should we need
+    case USBD_EVT_FUNC_CALL:
+      osal_queue_send(_usbd_q, event, in_isr);
+    break;
+
     default: break;
   }
 }
@@ -622,6 +621,8 @@ void dcd_event_xfer_complete (uint8_t rhport, uint8_t ep_addr, uint32_t xferred_
 //--------------------------------------------------------------------+
 // Helper
 //--------------------------------------------------------------------+
+
+// Helper to parse an pair of endpoint descriptors (IN & OUT)
 tusb_error_t usbd_open_edpt_pair(uint8_t rhport, tusb_desc_endpoint_t const* p_desc_ep, uint8_t xfer_type, uint8_t* ep_out, uint8_t* ep_in)
 {
   for(int i=0; i<2; i++)
@@ -645,7 +646,8 @@ tusb_error_t usbd_open_edpt_pair(uint8_t rhport, tusb_desc_endpoint_t const* p_d
   return TUSB_ERROR_NONE;
 }
 
-void usbd_defer_func(osal_task_func_t func, void* param, bool in_isr )
+// Helper to defer an isr function
+void usbd_defer_func(osal_task_func_t func, void* param, bool in_isr)
 {
   dcd_event_t event =
   {
@@ -656,7 +658,7 @@ void usbd_defer_func(osal_task_func_t func, void* param, bool in_isr )
   event.func_call.func  = func;
   event.func_call.param = param;
 
-  osal_queue_send(_usbd_q, &event, in_isr);
+  dcd_event_handler(&event, in_isr);
 }
 
 #endif
diff --git a/src/osal/osal_freertos.h b/src/osal/osal_freertos.h
index 52cadd798..704aafd64 100644
--- a/src/osal/osal_freertos.h
+++ b/src/osal/osal_freertos.h
@@ -139,7 +139,9 @@ static inline bool osal_mutex_unlock(osal_mutex_t mutex_hdl)
 //--------------------------------------------------------------------+
 // QUEUE API
 //--------------------------------------------------------------------+
-#define OSAL_QUEUE_DEF(_name, _depth, _type) \
+
+// role device/host is used by OS NONE for mutex (disable usb isr) only
+#define OSAL_QUEUE_DEF(_role, _name, _depth, _type) \
   static _type _name##_##buf[_depth];\
   osal_queue_def_t _name = { .depth = _depth, .item_sz = sizeof(_type), .buf = _name##_##buf };
 
diff --git a/src/osal/osal_mynewt.h b/src/osal/osal_mynewt.h
index cb09680e0..62b5b45e8 100644
--- a/src/osal/osal_mynewt.h
+++ b/src/osal/osal_mynewt.h
@@ -75,7 +75,9 @@ static inline void osal_task_delay(uint32_t msec)
 //--------------------------------------------------------------------+
 // QUEUE API
 //--------------------------------------------------------------------+
-#define OSAL_QUEUE_DEF(_name, _depth, _type) \
+
+// role device/host is used by OS NONE for mutex (disable usb isr) only
+#define OSAL_QUEUE_DEF(_role, _name, _depth, _type) \
   static _type _name##_##buf[_depth];\
   static struct os_event* _name##_##evbuf[_depth];\
   osal_queue_def_t _name = { .depth = _depth, .item_sz = sizeof(_type), .buf = _name##_##buf, .evbuf =  _name##_##evbuf};\
diff --git a/src/osal/osal_none.h b/src/osal/osal_none.h
index 40ecb9c37..115c50bdb 100644
--- a/src/osal/osal_none.h
+++ b/src/osal/osal_none.h
@@ -93,12 +93,11 @@ static inline void osal_semaphore_reset(osal_semaphore_t sem_hdl)
 static inline tusb_error_t osal_semaphore_wait(osal_semaphore_t sem_hdl, uint32_t msec) {
   (void) msec;
   while (true) {
-      while (sem_hdl->count == 0) {
-      }
-      if (sem_hdl->count == 0) {
-          sem_hdl->count--;
-          break;
-      }
+    while (sem_hdl->count == 0) { }
+    if (sem_hdl->count == 0) {
+      sem_hdl->count--;
+      break;
+    }
   }
   return TUSB_ERROR_NONE;
 }
@@ -124,40 +123,90 @@ static inline osal_mutex_t osal_mutex_create(osal_mutex_def_t* mdef)
 //--------------------------------------------------------------------+
 #include "common/tusb_fifo.h"
 
-#define OSAL_QUEUE_DEF(_name, _depth, _type)    TU_FIFO_DEF(_name, _depth, _type, false)
+typedef struct
+{
+    uint8_t role; // device or host
+    tu_fifo_t ff;
+}osal_queue_def_t;
 
-typedef tu_fifo_t  osal_queue_def_t;
-typedef tu_fifo_t* osal_queue_t;
+typedef osal_queue_def_t* osal_queue_t;
+
+// role device/host is used by OS NONE for mutex (disable usb isr) only
+#define OSAL_QUEUE_DEF(_role, _name, _depth, _type) \
+  uint8_t _name##_buf[_depth*sizeof(_type)];        \
+  osal_queue_def_t _name = {                        \
+    .role = _role,                                  \
+    .ff = {                                         \
+      .buffer       = _name##_buf,                  \
+      .depth        = _depth,                       \
+      .item_size    = sizeof(_type),                \
+      .overwritable = false,                        \
+    }\
+  }
+
+// lock queue by disable usb isr
+static inline void _osal_q_lock(osal_queue_t qhdl)
+{
+#if TUSB_OPT_DEVICE_ENABLED
+  extern void dcd_int_disable(uint8_t rhport);
+  if (qhdl->role == OPT_MODE_DEVICE) dcd_int_disable(TUD_OPT_RHPORT);
+#endif
+
+#if MODE_HOST_SUPPORTED
+  extern void hcd_int_disable(uint8_t rhport);
+  if (qhdl->role == OPT_MODE_HOST) hcd_int_disable(TUH_OPT_RHPORT);
+#endif
+}
+
+// unlock queue
+static inline void _osal_q_unlock(osal_queue_t qhdl)
+{
+#if TUSB_OPT_DEVICE_ENABLED
+  extern void dcd_int_enable(uint8_t rhport);
+  if (qhdl->role == OPT_MODE_DEVICE) dcd_int_enable(TUD_OPT_RHPORT);
+#endif
+
+#if MODE_HOST_SUPPORTED
+  extern void hcd_int_enable(uint8_t rhport);
+  if (qhdl->role == OPT_MODE_HOST) hcd_int_enable(TUH_OPT_RHPORT);
+#endif
+}
 
 static inline osal_queue_t osal_queue_create(osal_queue_def_t* qdef)
 {
-  tu_fifo_clear(qdef);
+  tu_fifo_clear(&qdef->ff);
   return (osal_queue_t) qdef;
 }
 
-static inline bool osal_queue_send(osal_queue_t const queue_hdl, void const * data, bool in_isr)
+static inline bool osal_queue_send(osal_queue_t const qhdl, void const * data, bool in_isr)
 {
   if (!in_isr) {
-    tusb_hal_int_disable_all();
+    _osal_q_lock(qhdl);
   }
-  bool success = tu_fifo_write( (tu_fifo_t*) queue_hdl, data);
+
+  bool success = tu_fifo_write(&qhdl->ff, data);
+
   if (!in_isr) {
-    tusb_hal_int_enable_all();
+    _osal_q_unlock(qhdl);
   }
+
   return success;
 }
 
-static inline void osal_queue_reset(osal_queue_t const queue_hdl)
+static inline void osal_queue_reset(osal_queue_t const qhdl)
 {
   // tusb_hal_int_disable_all();
-  tu_fifo_clear( (tu_fifo_t*) queue_hdl);
+  tu_fifo_clear(&qhdl->ff);
   // tusb_hal_int_enable_all();
 }
 
-static inline bool osal_queue_receive(osal_queue_t const queue_hdl, void* data) {
-  tusb_hal_int_disable_all();
-  bool success = tu_fifo_read(queue_hdl, data);
-  tusb_hal_int_enable_all();
+// non blocking
+static inline bool osal_queue_receive(osal_queue_t const qhdl, void* data)
+{
+  _osal_q_lock(qhdl);
+  bool success = tu_fifo_read(&qhdl->ff, data);
+  _osal_q_unlock(qhdl);
+
   return success;
 }
 
diff --git a/src/tusb_hal.h b/src/tusb_hal.h
index 301e8c2f2..804196ad2 100644
--- a/src/tusb_hal.h
+++ b/src/tusb_hal.h
@@ -55,38 +55,6 @@ extern "C" {
 // Only required to implement if using No RTOS (osal_none)
 uint32_t tusb_hal_millis(void);
 
-// TODO remove
-extern void dcd_int_enable (uint8_t rhport);
-extern void dcd_int_disable(uint8_t rhport);
-
-// Enable all ports' interrupt
-// TODO remove
-static inline void tusb_hal_int_enable_all(void)
-{
-#ifdef CFG_TUSB_RHPORT0_MODE
-  dcd_int_enable(0);
-#endif
-
-#ifdef CFG_TUSB_RHPORT0_MODE
-  dcd_int_enable(1);
-#endif
-}
-
-// Disable all ports' interrupt
-// TODO remove
-static inline void tusb_hal_int_disable_all(void)
-{
-#ifdef CFG_TUSB_RHPORT0_MODE
-  dcd_int_disable(0);
-#endif
-
-#ifdef CFG_TUSB_RHPORT0_MODE
-  dcd_int_disable(1);
-#endif
-}
-
-
-
 #ifdef __cplusplus
  }
 #endif
diff --git a/src/tusb_option.h b/src/tusb_option.h
index c558b30ff..6b84db21c 100644
--- a/src/tusb_option.h
+++ b/src/tusb_option.h
@@ -123,7 +123,6 @@
 // Which roothub port is configured as device
 #define TUD_OPT_RHPORT          ( (CFG_TUSB_RHPORT0_MODE & OPT_MODE_DEVICE) ? 0 : ((CFG_TUSB_RHPORT1_MODE & OPT_MODE_DEVICE) ? 1 : -1) )
 
-
 #if TUD_OPT_RHPORT == 0
 #define TUD_OPT_HIGH_SPEED      ( CFG_TUSB_RHPORT0_MODE & OPT_MODE_HIGH_SPEED )
 #else