2 files changed, 22 insertions, 14 deletions
diff --git a/src/class/msc/msc_device.c b/src/class/msc/msc_device.c
index 70ba956aa..b038d00f7 100644
--- a/src/class/msc/msc_device.c
+++ b/src/class/msc/msc_device.c
@@ -154,25 +154,33 @@ void mscd_reset(uint8_t rhport)
   tu_memclr(&_mscd_itf, sizeof(mscd_interface_t));
 }
 
-bool mscd_open(uint8_t rhport, tusb_desc_interface_t const * itf_desc, uint16_t *p_len)
+uint16_t mscd_open(uint8_t rhport, tusb_desc_interface_t const * itf_desc, uint16_t max_len)
 {
   // only support SCSI's BOT protocol
   TU_VERIFY(TUSB_CLASS_MSC    == itf_desc->bInterfaceClass &&
             MSC_SUBCLASS_SCSI == itf_desc->bInterfaceSubClass &&
-            MSC_PROTOCOL_BOT  == itf_desc->bInterfaceProtocol);
+            MSC_PROTOCOL_BOT  == itf_desc->bInterfaceProtocol, 0);
 
-  mscd_interface_t * p_msc = &_mscd_itf;
+  // msc driver length is fixed
+  uint16_t const drv_len = sizeof(tusb_desc_interface_t) + 2*sizeof(tusb_desc_endpoint_t);
 
-  // Open endpoint pair
-  TU_ASSERT( usbd_open_edpt_pair(rhport, tu_desc_next(itf_desc), 2, TUSB_XFER_BULK, &p_msc->ep_out, &p_msc->ep_in) );
+  // Max length mus be at least 1 interface + 2 endpoints
+  TU_ASSERT(max_len >= drv_len, 0);
 
+  mscd_interface_t * p_msc = &_mscd_itf;
   p_msc->itf_num = itf_desc->bInterfaceNumber;
-  (*p_len) = sizeof(tusb_desc_interface_t) + 2*sizeof(tusb_desc_endpoint_t);
+
+  // Open endpoint pair
+  TU_ASSERT( usbd_open_edpt_pair(rhport, tu_desc_next(itf_desc), 2, TUSB_XFER_BULK, &p_msc->ep_out, &p_msc->ep_in), 0 );
 
   // Prepare for Command Block Wrapper
-  TU_ASSERT( usbd_edpt_xfer(rhport, p_msc->ep_out, (uint8_t*) &p_msc->cbw, sizeof(msc_cbw_t)) );
+  if ( !usbd_edpt_xfer(rhport, p_msc->ep_out, (uint8_t*) &p_msc->cbw, sizeof(msc_cbw_t)) )
+  {
+    TU_LOG1_FAILED();
+    TU_BREAKPOINT();
+  }
 
-  return true;
+  return drv_len;
 }
 
 // Handle class control request
diff --git a/src/class/msc/msc_device.h b/src/class/msc/msc_device.h
index 66180777e..30ffd02e1 100644
--- a/src/class/msc/msc_device.h
+++ b/src/class/msc/msc_device.h
@@ -151,12 +151,12 @@ TU_ATTR_WEAK bool tud_msc_is_writable_cb(uint8_t lun);
 //--------------------------------------------------------------------+
 // Internal Class Driver API
 //--------------------------------------------------------------------+
-void mscd_init             (void);
-void mscd_reset            (uint8_t rhport);
-bool mscd_open             (uint8_t rhport, tusb_desc_interface_t const * itf_desc, uint16_t *p_length);
-bool mscd_control_request  (uint8_t rhport, tusb_control_request_t const * p_request);
-bool mscd_control_complete (uint8_t rhport, tusb_control_request_t const * p_request);
-bool mscd_xfer_cb          (uint8_t rhport, uint8_t ep_addr, xfer_result_t event, uint32_t xferred_bytes);
+void     mscd_init             (void);
+void     mscd_reset            (uint8_t rhport);
+uint16_t mscd_open             (uint8_t rhport, tusb_desc_interface_t const * itf_desc, uint16_t max_len);
+bool     mscd_control_request  (uint8_t rhport, tusb_control_request_t const * p_request);
+bool     mscd_control_complete (uint8_t rhport, tusb_control_request_t const * p_request);
+bool     mscd_xfer_cb          (uint8_t rhport, uint8_t ep_addr, xfer_result_t event, uint32_t xferred_bytes);
 
 #ifdef __cplusplus
  }