update cdc edpt read

src/class/cdc/cdc_device.c

@@ -77,15 +77,13 @@ static void _prep_out_transaction (uint8_t itf)
 {
   cdcd_interface_t* p_cdc = &_cdcd_itf[itf];
 
+  // Prepare for incoming data but only allow what we can store in the ring buffer.
+  uint16_t const available = tu_fifo_remaining(&p_cdc->rx_ff);
+  TU_VERIFY( available >= sizeof(p_cdc->epout_buf), );
+
   // claim endpoint
   TU_VERIFY( usbd_edpt_claim(TUD_OPT_RHPORT, p_cdc->ep_out), );
-
-  // Prepare for incoming data but only allow what we can store in the ring buffer.
-  uint16_t max_read = tu_fifo_remaining(&p_cdc->rx_ff);
-  if ( max_read >= sizeof(p_cdc->epout_buf) )
-  {
-    usbd_edpt_xfer(TUD_OPT_RHPORT, p_cdc->ep_out, p_cdc->epout_buf, sizeof(p_cdc->epout_buf));
-  }
+  usbd_edpt_xfer(TUD_OPT_RHPORT, p_cdc->ep_out, p_cdc->epout_buf, sizeof(p_cdc->epout_buf));
 }
 
 //--------------------------------------------------------------------+

src/device/usbd.c

@@ -1162,7 +1162,9 @@ bool usbd_edpt_xfer(uint8_t rhport, uint8_t ep_addr, uint8_t * buffer, uint16_t
     return true;
   }else
   {
+    // DCD error, mark endpoint as ready to allow next transfer
     _usbd_dev.ep_status[epnum][dir].busy = false;
+    _usbd_dev.ep_status[epnum][dir].claimed = 0;
     TU_LOG2("failed\r\n");
     TU_BREAKPOINT();
     return false;