Merge pull request #2994 from hathach/enhance-hub

Enhance hub driver

5 files changed, 366 insertions, 364 deletions

diff --git a/src/host/hub.c b/src/host/hub.c
index e97014443..93b4a3a84 100644
--- a/src/host/hub.c
+++ b/src/host/hub.c
@@ -40,29 +40,36 @@
 //--------------------------------------------------------------------+
 // MACRO CONSTANT TYPEDEF
 //--------------------------------------------------------------------+
-typedef struct
-{
+typedef struct {
   uint8_t itf_num;
   uint8_t ep_in;
-  uint8_t port_count;
 
-  CFG_TUH_MEM_ALIGN uint8_t status_change;
-  CFG_TUH_MEM_ALIGN hub_port_status_response_t port_status;
-  CFG_TUH_MEM_ALIGN hub_status_response_t hub_status;
+  // from hub descriptor
+  uint8_t bNbrPorts;
+  uint8_t bPwrOn2PwrGood; // port power on to good, in 2ms unit
+  // uint16_t wHubCharacteristics;
+
+  hub_port_status_response_t port_status;
 } hub_interface_t;
 
-CFG_TUH_MEM_SECTION static hub_interface_t hub_data[CFG_TUH_HUB];
-CFG_TUH_MEM_SECTION CFG_TUH_MEM_ALIGN static uint8_t _hub_buffer[sizeof(descriptor_hub_desc_t)];
+typedef struct {
+  TUH_EPBUF_DEF(status_change, 4); // interrupt endpoint
+  TUH_EPBUF_DEF(ctrl_buf, CFG_TUH_HUB_BUFSIZE);
+} hub_epbuf_t;
+
+static hub_interface_t hub_itfs[CFG_TUH_HUB];
+CFG_TUH_MEM_SECTION static hub_epbuf_t hub_epbufs[CFG_TUH_HUB];
+
+TU_ATTR_ALWAYS_INLINE static inline hub_interface_t* get_hub_itf(uint8_t daddr) {
+  return &hub_itfs[daddr-1-CFG_TUH_DEVICE_MAX];
+}
 
-TU_ATTR_ALWAYS_INLINE
-static inline hub_interface_t* get_itf(uint8_t dev_addr)
-{
-  return &hub_data[dev_addr-1-CFG_TUH_DEVICE_MAX];
+TU_ATTR_ALWAYS_INLINE static inline hub_epbuf_t* get_hub_epbuf(uint8_t daddr) {
+  return &hub_epbufs[daddr-1-CFG_TUH_DEVICE_MAX];
 }
 
-#if CFG_TUSB_DEBUG >= 2
-static char const* const _hub_feature_str[] =
-{
+#if CFG_TUSB_DEBUG >= HUB_DEBUG
+static char const* const _hub_feature_str[] = {
   [HUB_FEATURE_PORT_CONNECTION          ] = "PORT_CONNECTION",
   [HUB_FEATURE_PORT_ENABLE              ] = "PORT_ENABLE",
   [HUB_FEATURE_PORT_SUSPEND             ] = "PORT_SUSPEND",
@@ -84,12 +91,9 @@ static char const* const _hub_feature_str[] =
 // HUB
 //--------------------------------------------------------------------+
 bool hub_port_clear_feature(uint8_t hub_addr, uint8_t hub_port, uint8_t feature,
-                            tuh_xfer_cb_t complete_cb, uintptr_t user_data)
-{
-  tusb_control_request_t const request =
-  {
-    .bmRequestType_bit =
-    {
+                            tuh_xfer_cb_t complete_cb, uintptr_t user_data) {
+  tusb_control_request_t const request = {
+    .bmRequestType_bit = {
       .recipient = (hub_port == 0) ? TUSB_REQ_RCPT_DEVICE : TUSB_REQ_RCPT_OTHER,
       .type      = TUSB_REQ_TYPE_CLASS,
       .direction = TUSB_DIR_OUT
@@ -100,8 +104,7 @@ bool hub_port_clear_feature(uint8_t hub_addr, uint8_t hub_port, uint8_t feature,
     .wLength  = 0
   };
 
-  tuh_xfer_t xfer =
-  {
+  tuh_xfer_t xfer = {
     .daddr       = hub_addr,
     .ep_addr     = 0,
     .setup       = &request,
@@ -110,18 +113,15 @@ bool hub_port_clear_feature(uint8_t hub_addr, uint8_t hub_port, uint8_t feature,
     .user_data   = user_data
   };
 
-  TU_LOG2("HUB Clear Feature: %s, addr = %u port = %u\r\n", _hub_feature_str[feature], hub_addr, hub_port);
-  TU_ASSERT( tuh_control_xfer(&xfer) );
+  TU_LOG_DRV("HUB Clear Feature: %s, addr = %u port = %u\r\n", _hub_feature_str[feature], hub_addr, hub_port);
+  TU_ASSERT(tuh_control_xfer(&xfer));
   return true;
 }
 
 bool hub_port_set_feature(uint8_t hub_addr, uint8_t hub_port, uint8_t feature,
-                          tuh_xfer_cb_t complete_cb, uintptr_t user_data)
-{
-  tusb_control_request_t const request =
-  {
-    .bmRequestType_bit =
-    {
+                          tuh_xfer_cb_t complete_cb, uintptr_t user_data) {
+  tusb_control_request_t const request = {
+    .bmRequestType_bit = {
       .recipient = (hub_port == 0) ? TUSB_REQ_RCPT_DEVICE : TUSB_REQ_RCPT_OTHER,
       .type      = TUSB_REQ_TYPE_CLASS,
       .direction = TUSB_DIR_OUT
@@ -132,8 +132,7 @@ bool hub_port_set_feature(uint8_t hub_addr, uint8_t hub_port, uint8_t feature,
     .wLength  = 0
   };
 
-  tuh_xfer_t xfer =
-  {
+  tuh_xfer_t xfer = {
     .daddr       = hub_addr,
     .ep_addr     = 0,
     .setup       = &request,
@@ -142,18 +141,15 @@ bool hub_port_set_feature(uint8_t hub_addr, uint8_t hub_port, uint8_t feature,
     .user_data   = user_data
   };
 
-  TU_LOG2("HUB Set Feature: %s, addr = %u port = %u\r\n", _hub_feature_str[feature], hub_addr, hub_port);
+  TU_LOG_DRV("HUB Set Feature: %s, addr = %u port = %u\r\n", _hub_feature_str[feature], hub_addr, hub_port);
   TU_ASSERT( tuh_control_xfer(&xfer) );
   return true;
 }
 
 bool hub_port_get_status(uint8_t hub_addr, uint8_t hub_port, void* resp,
-                         tuh_xfer_cb_t complete_cb, uintptr_t user_data)
-{
-  tusb_control_request_t const request =
-  {
-    .bmRequestType_bit =
-    {
+                         tuh_xfer_cb_t complete_cb, uintptr_t user_data) {
+  tusb_control_request_t const request = {
+    .bmRequestType_bit = {
       .recipient = (hub_port == 0) ? TUSB_REQ_RCPT_DEVICE : TUSB_REQ_RCPT_OTHER,
       .type      = TUSB_REQ_TYPE_CLASS,
       .direction = TUSB_DIR_IN
@@ -161,11 +157,10 @@ bool hub_port_get_status(uint8_t hub_addr, uint8_t hub_port, void* resp,
     .bRequest = HUB_REQUEST_GET_STATUS,
     .wValue   = 0,
     .wIndex   = hub_port,
-    .wLength  = 4
+    .wLength  = tu_htole16(4)
   };
 
-  tuh_xfer_t xfer =
-  {
+  tuh_xfer_t xfer = {
     .daddr       = hub_addr,
     .ep_addr     = 0,
     .setup       = &request,
@@ -174,7 +169,7 @@ bool hub_port_get_status(uint8_t hub_addr, uint8_t hub_port, void* resp,
     .user_data   = user_data
   };
 
-  TU_LOG2("HUB Get Port Status: addr = %u port = %u\r\n", hub_addr, hub_port);
+  TU_LOG_DRV("HUB Get Port Status: addr = %u port = %u\r\n", hub_addr, hub_port);
   TU_VERIFY( tuh_control_xfer(&xfer) );
   return true;
 }
@@ -183,7 +178,7 @@ bool hub_port_get_status(uint8_t hub_addr, uint8_t hub_port, void* resp,
 // CLASS-USBH API (don't require to verify parameters)
 //--------------------------------------------------------------------+
 bool hub_init(void) {
-  tu_memclr(hub_data, sizeof(hub_data));
+  tu_memclr(hub_itfs, sizeof(hub_itfs));
   return true;
 }
 
@@ -191,40 +186,32 @@ bool hub_deinit(void) {
   return true;
 }
 
-bool hub_open(uint8_t rhport, uint8_t dev_addr, tusb_desc_interface_t const *itf_desc, uint16_t max_len)
-{
+bool hub_open(uint8_t rhport, uint8_t dev_addr, tusb_desc_interface_t const *itf_desc, uint16_t max_len) {
   (void) rhport;
 
   TU_VERIFY(TUSB_CLASS_HUB == itf_desc->bInterfaceClass &&
             0              == itf_desc->bInterfaceSubClass);
+  TU_VERIFY(itf_desc->bInterfaceProtocol <= 1); // not support multiple TT yet
 
-  // hub driver does not support multiple TT yet
-  TU_VERIFY(itf_desc->bInterfaceProtocol <= 1);
-
-  // msc driver length is fixed
   uint16_t const drv_len = sizeof(tusb_desc_interface_t) + sizeof(tusb_desc_endpoint_t);
   TU_ASSERT(drv_len <= max_len);
 
-  //------------- Interrupt Status endpoint -------------//
+  // Interrupt Status endpoint
   tusb_desc_endpoint_t const *desc_ep = (tusb_desc_endpoint_t const *) tu_desc_next(itf_desc);
-
   TU_ASSERT(TUSB_DESC_ENDPOINT  == desc_ep->bDescriptorType &&
             TUSB_XFER_INTERRUPT == desc_ep->bmAttributes.xfer, 0);
-
   TU_ASSERT(tuh_edpt_open(dev_addr, desc_ep));
 
-  hub_interface_t* p_hub = get_itf(dev_addr);
-
+  hub_interface_t* p_hub = get_hub_itf(dev_addr);
   p_hub->itf_num = itf_desc->bInterfaceNumber;
   p_hub->ep_in   = desc_ep->bEndpointAddress;
 
   return true;
 }
 
-void hub_close(uint8_t dev_addr)
-{
+void hub_close(uint8_t dev_addr) {
   TU_VERIFY(dev_addr > CFG_TUH_DEVICE_MAX, );
-  hub_interface_t* p_hub = get_itf(dev_addr);
+  hub_interface_t* p_hub = get_hub_itf(dev_addr);
 
   if (p_hub->ep_in) {
     TU_LOG_DRV("  HUB close addr = %d\r\n", dev_addr);
@@ -232,30 +219,33 @@ void hub_close(uint8_t dev_addr)
   }
 }
 
-bool hub_edpt_status_xfer(uint8_t dev_addr)
-{
-  hub_interface_t* hub_itf = get_itf(dev_addr);
-  return usbh_edpt_xfer(dev_addr, hub_itf->ep_in, &hub_itf->status_change, 1);
-}
+bool hub_edpt_status_xfer(uint8_t daddr) {
+  hub_interface_t* p_hub = get_hub_itf(daddr);
+  hub_epbuf_t* p_epbuf = get_hub_epbuf(daddr);
+
+  TU_VERIFY(usbh_edpt_claim(daddr, p_hub->ep_in));
+  if (!usbh_edpt_xfer(daddr, p_hub->ep_in, p_epbuf->status_change, 1)) {
+    usbh_edpt_release(daddr, p_hub->ep_in);
+    return false;
+  }
 
+  return true;
+}
 
 //--------------------------------------------------------------------+
 // Set Configure
 //--------------------------------------------------------------------+
-
 static void config_set_port_power (tuh_xfer_t* xfer);
 static void config_port_power_complete (tuh_xfer_t* xfer);
 
-bool hub_set_config(uint8_t dev_addr, uint8_t itf_num)
-{
-  hub_interface_t* p_hub = get_itf(dev_addr);
+bool hub_set_config(uint8_t dev_addr, uint8_t itf_num) {
+  hub_interface_t* p_hub = get_hub_itf(dev_addr);
   TU_ASSERT(itf_num == p_hub->itf_num);
+  hub_epbuf_t* p_epbuf = get_hub_epbuf(dev_addr);
 
   // Get Hub Descriptor
-  tusb_control_request_t const request =
-  {
-    .bmRequestType_bit =
-    {
+  tusb_control_request_t const request = {
+    .bmRequestType_bit = {
       .recipient = TUSB_REQ_RCPT_DEVICE,
       .type      = TUSB_REQ_TYPE_CLASS,
       .direction = TUSB_DIR_IN
@@ -263,34 +253,33 @@ bool hub_set_config(uint8_t dev_addr, uint8_t itf_num)
     .bRequest = HUB_REQUEST_GET_DESCRIPTOR,
     .wValue   = 0,
     .wIndex   = 0,
-    .wLength  = sizeof(descriptor_hub_desc_t)
+    .wLength  = sizeof(hub_desc_cs_t)
   };
 
-  tuh_xfer_t xfer =
-  {
+  tuh_xfer_t xfer = {
     .daddr       = dev_addr,
     .ep_addr     = 0,
     .setup       = &request,
-    .buffer      = _hub_buffer,
+    .buffer      = p_epbuf->ctrl_buf,
     .complete_cb = config_set_port_power,
     .user_data    = 0
   };
 
-  TU_ASSERT( tuh_control_xfer(&xfer) );
-
+  TU_ASSERT(tuh_control_xfer(&xfer));
   return true;
 }
 
-static void config_set_port_power (tuh_xfer_t* xfer)
-{
+static void config_set_port_power (tuh_xfer_t* xfer) {
   TU_ASSERT(XFER_RESULT_SUCCESS == xfer->result, );
 
   uint8_t const daddr = xfer->daddr;
-  hub_interface_t* p_hub = get_itf(daddr);
+  hub_interface_t* p_hub = get_hub_itf(daddr);
+  hub_epbuf_t* p_epbuf = get_hub_epbuf(daddr);
 
   // only use number of ports in hub descriptor
-  descriptor_hub_desc_t const* desc_hub = (descriptor_hub_desc_t const*) _hub_buffer;
-  p_hub->port_count = desc_hub->bNbrPorts;
+  hub_desc_cs_t const* desc_hub = (hub_desc_cs_t const*) p_epbuf->ctrl_buf;
+  p_hub->bNbrPorts = desc_hub->bNbrPorts;
+  p_hub->bPwrOn2PwrGood = desc_hub->bPwrOn2PwrGood;
 
   // May need to GET_STATUS
 
@@ -299,22 +288,22 @@ static void config_set_port_power (tuh_xfer_t* xfer)
   hub_port_set_feature(daddr, hub_port, HUB_FEATURE_PORT_POWER, config_port_power_complete, 0);
 }
 
-static void config_port_power_complete (tuh_xfer_t* xfer)
-{
+static void config_port_power_complete (tuh_xfer_t* xfer) {
   TU_ASSERT(XFER_RESULT_SUCCESS == xfer->result, );
 
   uint8_t const daddr = xfer->daddr;
-  hub_interface_t* p_hub = get_itf(daddr);
+  hub_interface_t* p_hub = get_hub_itf(daddr);
 
-  if (xfer->setup->wIndex == p_hub->port_count)
-  {
+  if (xfer->setup->wIndex == p_hub->bNbrPorts) {
     // All ports are power -> queue notification status endpoint and
     // complete the SET CONFIGURATION
-    TU_ASSERT( usbh_edpt_xfer(daddr, p_hub->ep_in, &p_hub->status_change, 1), );
-
+    if (!hub_edpt_status_xfer(daddr)) {
+      TU_MESS_FAILED();
+      TU_BREAKPOINT();
+    }
+    // delay bPwrOn2PwrGood * 2 ms before set configuration complete
     usbh_driver_set_config_complete(daddr, p_hub->itf_num);
-  }else
-  {
+  } else {
     // power next port
     uint8_t const hub_port = (uint8_t) (xfer->setup->wIndex + 1);
     hub_port_set_feature(daddr, hub_port, HUB_FEATURE_PORT_POWER, config_port_power_complete, 0);
@@ -324,180 +313,162 @@ static void config_port_power_complete (tuh_xfer_t* xfer)
 //--------------------------------------------------------------------+
 // Connection Changes
 //--------------------------------------------------------------------+
-
-static void hub_port_get_status_complete (tuh_xfer_t* xfer);
-static void hub_get_status_complete (tuh_xfer_t* xfer);
+static void get_status_complete (tuh_xfer_t* xfer);
+static void port_get_status_complete (tuh_xfer_t* xfer);
+static void port_clear_feature_complete_stub(tuh_xfer_t* xfer);
 static void connection_clear_conn_change_complete (tuh_xfer_t* xfer);
 static void connection_port_reset_complete (tuh_xfer_t* xfer);
 
 // callback as response of interrupt endpoint polling
-bool hub_xfer_cb(uint8_t dev_addr, uint8_t ep_addr, xfer_result_t result, uint32_t xferred_bytes) {
-  (void) xferred_bytes; // TODO can be more than 1 for hub with lots of ports
+bool hub_xfer_cb(uint8_t daddr, uint8_t ep_addr, xfer_result_t result, uint32_t xferred_bytes) {
+  (void) xferred_bytes;
   (void) ep_addr;
-  TU_VERIFY(result == XFER_RESULT_SUCCESS);
 
-  hub_interface_t* p_hub = get_itf(dev_addr);
+  bool processed = false; // true if new status is processed
 
-  uint8_t const status_change = p_hub->status_change;
-  TU_LOG2("  Hub Status Change = 0x%02X\r\n", status_change);
-
-  if ( status_change == 0 ) {
-    // The status change event was neither for the hub, nor for any of its ports.
-    // This shouldn't happen, but it does with some devices.
-    // Initiate the next interrupt poll here.
-    return hub_edpt_status_xfer(dev_addr);
-  }
+  if (result == XFER_RESULT_SUCCESS) {
+    hub_interface_t* p_hub = get_hub_itf(daddr);
+    hub_epbuf_t *p_epbuf = get_hub_epbuf(daddr);
+    const uint8_t status_change = p_epbuf->status_change[0];
+    TU_LOG_DRV("  Hub Status Change = 0x%02X\r\n", status_change);
 
-  if (tu_bit_test(status_change, 0)) {
-    // Hub bit 0 is for the hub device events
-    if (hub_port_get_status(dev_addr, 0, &p_hub->hub_status, hub_get_status_complete, 0) == false) {
-      //Hub status control transfer failed, retry
-      hub_edpt_status_xfer(dev_addr);
-    }
-  }
-  else {
-    // Hub bits 1 to n are hub port events
-    for (uint8_t port=1; port <= p_hub->port_count; port++) {
-      if ( tu_bit_test(status_change, port) ) {
-        if (hub_port_get_status(dev_addr, port, &p_hub->port_status, hub_port_get_status_complete, 0) == false) {
-          //Hub status control transfer failed, retry
-          hub_edpt_status_xfer(dev_addr);
+    if (status_change == 0) {
+      // The status change event was neither for the hub, nor for any of its ports.
+      // This shouldn't happen, but it does with some devices. Re-Initiate the interrupt poll.
+      processed = false;
+    } else if (tu_bit_test(status_change, 0)) {
+      // Hub bit 0 is for the hub device events
+      processed = hub_get_status(daddr, p_epbuf->ctrl_buf, get_status_complete, 0);
+    } else {
+      // Hub bits 1 to n are hub port events
+      for (uint8_t port=1; port <= p_hub->bNbrPorts; port++) {
+        if (tu_bit_test(status_change, port)) {
+          processed = hub_port_get_status(daddr, port, p_epbuf->ctrl_buf, port_get_status_complete, 0);
+          break; // after completely processed one port, we will re-queue the status poll and handle next one
         }
-        break;
       }
     }
   }
 
-  // NOTE: next status transfer is queued by usbh.c after handling this request
+  // If new status event is processed: next status pool is queued by usbh.c after handled this request
+  // Otherwise re-queue the status poll here
+  if (!processed) {
+    TU_ASSERT(hub_edpt_status_xfer(daddr));
+  }
+
   return true;
 }
 
-static void hub_clear_feature_complete_stub(tuh_xfer_t* xfer)
-{
-  TU_ASSERT(xfer->result == XFER_RESULT_SUCCESS, );
+static void port_clear_feature_complete_stub(tuh_xfer_t* xfer) {
   hub_edpt_status_xfer(xfer->daddr);
 }
 
-static void hub_get_status_complete (tuh_xfer_t* xfer)
-{
-  TU_ASSERT(xfer->result == XFER_RESULT_SUCCESS, );
+static void get_status_complete(tuh_xfer_t *xfer) {
+  const uint8_t daddr = xfer->daddr;
 
-  uint8_t const daddr = xfer->daddr;
-  hub_interface_t* p_hub = get_itf(daddr);
-  uint8_t const port_num = (uint8_t) tu_le16toh(xfer->setup->wIndex);
-  TU_ASSERT(port_num == 0 , );
+  bool processed = false; // true if new status is processed
+  if (xfer->result == XFER_RESULT_SUCCESS) {
+    hub_status_response_t hub_status = *((const hub_status_response_t *) (uintptr_t) xfer->buffer);
 
-  TU_LOG2("HUB Got hub status, addr = %u, status = %04x\r\n", daddr, p_hub->hub_status.change.value);
+    TU_LOG_DRV("HUB Got hub status, addr = %u, status = %04x\r\n", daddr, hub_status.change.value);
 
-  if (p_hub->hub_status.change.local_power_source)
-  {
-    TU_LOG2("HUB Local Power Change, addr = %u\r\n", daddr);
-    hub_port_clear_feature(daddr, port_num, HUB_FEATURE_HUB_LOCAL_POWER_CHANGE, hub_clear_feature_complete_stub, 0);
+    if (hub_status.change.local_power_source) {
+      TU_LOG_DRV("  Local Power Change\r\n");
+      processed = hub_clear_feature(daddr, HUB_FEATURE_HUB_LOCAL_POWER_CHANGE, port_clear_feature_complete_stub, 0);
+    } else if (hub_status.change.over_current) {
+      TU_LOG_DRV("  Over Current\r\n");
+      processed = hub_clear_feature(daddr, HUB_FEATURE_HUB_OVER_CURRENT_CHANGE, port_clear_feature_complete_stub, 0);
+    }
   }
-  else if (p_hub->hub_status.change.over_current)
-  {
-    TU_LOG1("HUB Over Current, addr = %u\r\n", daddr);
-    hub_port_clear_feature(daddr, port_num, HUB_FEATURE_HUB_OVER_CURRENT_CHANGE, hub_clear_feature_complete_stub, 0);
+
+  if (!processed) {
+    TU_ASSERT(hub_edpt_status_xfer(daddr), );
   }
 }
 
-static void hub_port_get_status_complete (tuh_xfer_t* xfer)
-{
-  TU_ASSERT(xfer->result == XFER_RESULT_SUCCESS, );
+static void port_get_status_complete(tuh_xfer_t *xfer) {
+  const uint8_t daddr = xfer->daddr;
+  bool processed = false; // true if new status is processed
 
-  uint8_t const daddr = xfer->daddr;
-  hub_interface_t* p_hub = get_itf(daddr);
-  uint8_t const port_num = (uint8_t) tu_le16toh(xfer->setup->wIndex);
+  if (xfer->result == XFER_RESULT_SUCCESS) {
+    const uint8_t port_num = (uint8_t) tu_le16toh(xfer->setup->wIndex);
+    hub_interface_t *p_hub = get_hub_itf(daddr);
+    p_hub->port_status = *((const hub_port_status_response_t *) (uintptr_t) xfer->buffer);
 
-  // Connection change
-  if (p_hub->port_status.change.connection)
-  {
-    // Port is powered and enabled
-    //TU_VERIFY(port_status.status_current.port_power && port_status.status_current.port_enable, );
+    // Clear port status change interrupts
+    if (p_hub->port_status.change.connection) {
+      // Connection change
+      // Port is powered and enabled
+      //TU_VERIFY(port_status.status_current.port_power && port_status.status_current.port_enable, );
 
-    // Acknowledge Port Connection Change
-    hub_port_clear_feature(daddr, port_num, HUB_FEATURE_PORT_CONNECTION_CHANGE, connection_clear_conn_change_complete, 0);
-  }else
-  {
-    // Clear other port status change interrupts. TODO Not currently handled - just cleared.
-    if (p_hub->port_status.change.port_enable)
-    {
-      hub_port_clear_feature(daddr, port_num, HUB_FEATURE_PORT_ENABLE_CHANGE, hub_clear_feature_complete_stub, 0);
-    }
-    else if (p_hub->port_status.change.suspend)
-    {
-      hub_port_clear_feature(daddr, port_num, HUB_FEATURE_PORT_SUSPEND_CHANGE, hub_clear_feature_complete_stub, 0);
-    }
-    else if (p_hub->port_status.change.over_current)
-    {
-      hub_port_clear_feature(daddr, port_num, HUB_FEATURE_PORT_OVER_CURRENT_CHANGE, hub_clear_feature_complete_stub, 0);
-    }
-    else if (p_hub->port_status.change.reset)
-    {
-      hub_port_clear_feature(daddr, port_num, HUB_FEATURE_PORT_RESET_CHANGE, hub_clear_feature_complete_stub, 0);
+      // Acknowledge Port Connection Change
+      processed = hub_port_clear_feature(daddr, port_num, HUB_FEATURE_PORT_CONNECTION_CHANGE, connection_clear_conn_change_complete, 0);
+    } else if (p_hub->port_status.change.port_enable) {
+      processed = hub_port_clear_feature(daddr, port_num, HUB_FEATURE_PORT_ENABLE_CHANGE, port_clear_feature_complete_stub, 0);
+    } else if (p_hub->port_status.change.suspend) {
+      processed = hub_port_clear_feature(daddr, port_num, HUB_FEATURE_PORT_SUSPEND_CHANGE, port_clear_feature_complete_stub, 0);
+    } else if (p_hub->port_status.change.over_current) {
+      processed = hub_port_clear_feature(daddr, port_num, HUB_FEATURE_PORT_OVER_CURRENT_CHANGE, port_clear_feature_complete_stub, 0);
+    } else if (p_hub->port_status.change.reset) {
+      processed = hub_port_clear_feature(daddr, port_num, HUB_FEATURE_PORT_RESET_CHANGE, port_clear_feature_complete_stub, 0);
     }
-    // Other changes are: L1 state
-    // TODO clear change
+  }
 
-    else
-    {
-      // prepare for next hub status
-      // TODO continue with status_change, or maybe we can do it again with status
-      hub_edpt_status_xfer(daddr);
-    }
+  if (!processed) {
+    TU_ASSERT(hub_edpt_status_xfer(daddr), );
   }
 }
 
-static void connection_clear_conn_change_complete (tuh_xfer_t* xfer)
-{
-  TU_ASSERT(xfer->result == XFER_RESULT_SUCCESS, );
+static void connection_clear_conn_change_complete (tuh_xfer_t* xfer) {
+  const uint8_t daddr = xfer->daddr;
 
-  uint8_t const daddr = xfer->daddr;
-  hub_interface_t* p_hub = get_itf(daddr);
-  uint8_t const port_num = (uint8_t) tu_le16toh(xfer->setup->wIndex);
+  if (xfer->result != XFER_RESULT_SUCCESS) {
+    TU_ASSERT(hub_edpt_status_xfer(daddr), );
+    return;
+  }
+
+  hub_interface_t *p_hub = get_hub_itf(daddr);
+  const uint8_t port_num = (uint8_t) tu_le16toh(xfer->setup->wIndex);
 
-  if ( p_hub->port_status.status.connection )
-  {
+  if (p_hub->port_status.status.connection) {
     // Reset port if attach event
     hub_port_reset(daddr, port_num, connection_port_reset_complete, 0);
-  }else
-  {
+  } else {
     // submit detach event
-    hcd_event_t event =
-    {
+    const hcd_event_t event = {
       .rhport     = usbh_get_rhport(daddr),
       .event_id   = HCD_EVENT_DEVICE_REMOVE,
-      .connection =
-       {
+      .connection = {
          .hub_addr = daddr,
          .hub_port = port_num
        }
     };
-
     hcd_event_handler(&event, false);
   }
 }
 
-static void connection_port_reset_complete (tuh_xfer_t* xfer)
-{
-  TU_ASSERT(xfer->result == XFER_RESULT_SUCCESS, );
+static void connection_port_reset_complete (tuh_xfer_t* xfer) {
+  const uint8_t daddr = xfer->daddr;
 
-  uint8_t const daddr = xfer->daddr;
-  // hub_interface_t* p_hub = get_itf(daddr);
-  uint8_t const port_num = (uint8_t) tu_le16toh(xfer->setup->wIndex);
+  if (xfer->result != XFER_RESULT_SUCCESS) {
+    // retry port reset if failed
+    if (!tuh_control_xfer(xfer)) {
+      TU_ASSERT(hub_edpt_status_xfer(daddr), ); // back to status poll if failed to queue request
+    }
+    return;
+  }
+
+  const uint8_t port_num = (uint8_t) tu_le16toh(xfer->setup->wIndex);
 
   // submit attach event
-  hcd_event_t event =
-  {
+  hcd_event_t event = {
     .rhport     = usbh_get_rhport(daddr),
     .event_id   = HCD_EVENT_DEVICE_ATTACH,
-    .connection =
-    {
+    .connection = {
       .hub_addr = daddr,
       .hub_port = port_num
     }
   };
-
   hcd_event_handler(&event, false);
 }
 
diff --git a/src/host/hub.h b/src/host/hub.h
index 385efe6b2..e4e576661 100644
--- a/src/host/hub.h
+++ b/src/host/hub.h
@@ -24,17 +24,8 @@
  * This file is part of the TinyUSB stack.
  */
 
-/** \ingroup group_class
- *  \defgroup ClassDriver_Hub Hub (Host only)
- *  \details  Like most PC's OS, Hub support is completely hidden from Application. In fact, application cannot determine whether
- *            a device is mounted directly via roothub or via a hub's port. All Hub-related procedures are performed and managed
- *            by tinyusb stack. Unless you are trying to develop the stack itself, there are nothing else can be used by Application.
- *  \note     Due to my laziness, only 1-level of Hub is supported. In other way, the stack cannot mount a hub via another hub.
- *  @{
- */
-
-#ifndef _TUSB_HUB_H_
-#define _TUSB_HUB_H_
+#ifndef TUSB_HUB_H_
+#define TUSB_HUB_H_
 
 #include "common/tusb_common.h"
 
@@ -42,63 +33,23 @@
  extern "C" {
 #endif
 
-//D1...D0: Logical Power Switching Mode
-//00:  Ganged power switching (all ports’power at
-//once)
-//01:  Individual port power switching
-//1X:  Reserved. Used only on 1.0 compliant hubs
-//that implement no power switching
-//D2:  Identifies a Compound Device
-//0: Hub is not part of a compound device.
-//1: Hub is part of a compound device.
-//D4...D3: Over-current Protection Mode
-//00: Global Over-current Protection. The hub
-//reports over-current as a summation of all
-//ports’current draw, without a breakdown of
-//individual port over-current status.
-//01: Individual Port Over-current Protection. The
-//hub reports over-current on a per-port basis.
-//Each port has an over-current status.
-//1X: No Over-current Protection. This option is
-//allowed only for bus-powered hubs that do not
-//implement over-current protection.
-//
-//D6...D5: TT Think TIme
-//00:  TT requires at most 8 FS bit times of inter
-//transaction gap on a full-/low-speed
-//downstream bus.
-//01:  TT requires at most 16 FS bit times.
-//10:  TT requires at most 24 FS bit times.
-//11:  TT requires at most 32 FS bit times.
-//D7: Port Indicators Supported
-//0:  Port Indicators are not supported on its
-//downstream facing ports and the
-//PORT_INDICATOR request has no effect.
-//1:  Port Indicators are supported on its
-//downstream facing ports and the
-//PORT_INDICATOR request controls the
-//indicators. See Section 11.5.3.
-//D15...D8: Reserved
-
-typedef struct TU_ATTR_PACKED{
-  uint8_t  bLength           ; ///< Size of descriptor
-  uint8_t  bDescriptorType   ; ///< Other_speed_Configuration Type
-  uint8_t  bNbrPorts;
-  uint16_t wHubCharacteristics;
-  uint8_t  bPwrOn2PwrGood;
-  uint8_t  bHubContrCurrent;
-  uint8_t  DeviceRemovable; // bitmap each bit for a port (from bit1)
-  uint8_t  PortPwrCtrlMask; // just for compatibility, should be 0xff
-} descriptor_hub_desc_t;
+//--------------------------------------------------------------------+
+// Configuration
+//--------------------------------------------------------------------+
 
-TU_VERIFY_STATIC( sizeof(descriptor_hub_desc_t) == 9, "size is not correct");
+#ifndef CFG_TUH_HUB_BUFSIZE
+  #define CFG_TUH_HUB_BUFSIZE 12
+#endif
 
+//--------------------------------------------------------------------+
+//
+//--------------------------------------------------------------------+
 enum {
   HUB_REQUEST_GET_STATUS      = 0  ,
   HUB_REQUEST_CLEAR_FEATURE   = 1  ,
-
+  // 2 is reserved
   HUB_REQUEST_SET_FEATURE     = 3  ,
-
+  // 4-5 are reserved
   HUB_REQUEST_GET_DESCRIPTOR  = 6  ,
   HUB_REQUEST_SET_DESCRIPTOR  = 7  ,
   HUB_REQUEST_CLEAR_TT_BUFFER = 8  ,
@@ -118,10 +69,10 @@ enum{
   HUB_FEATURE_PORT_SUSPEND             = 2,
   HUB_FEATURE_PORT_OVER_CURRENT        = 3,
   HUB_FEATURE_PORT_RESET               = 4,
-
+  // 5-7 are reserved
   HUB_FEATURE_PORT_POWER               = 8,
   HUB_FEATURE_PORT_LOW_SPEED           = 9,
-
+  // 10-15 are reserved
   HUB_FEATURE_PORT_CONNECTION_CHANGE   = 16,
   HUB_FEATURE_PORT_ENABLE_CHANGE       = 17,
   HUB_FEATURE_PORT_SUSPEND_CHANGE      = 18,
@@ -131,6 +82,41 @@ enum{
   HUB_FEATURE_PORT_INDICATOR           = 22
 };
 
+enum {
+  HUB_CHARS_POWER_GANGED_SWITCHING = 0,
+  HUB_CHARS_POWER_INDIVIDUAL_SWITCHING = 1,
+};
+
+enum {
+  HUB_CHARS_OVER_CURRENT_GLOBAL = 0,
+  HUB_CHARS_OVER_CURRENT_INDIVIDUAL = 1,
+};
+
+typedef struct TU_ATTR_PACKED{
+  uint8_t  bLength           ; ///< Size of descriptor
+  uint8_t  bDescriptorType   ; ///< Other_speed_Configuration Type
+  uint8_t  bNbrPorts;
+  uint16_t wHubCharacteristics;
+  uint8_t  bPwrOn2PwrGood;
+  uint8_t  bHubContrCurrent;
+  uint8_t  DeviceRemovable; // bitmap each bit for a port (from bit1)
+  uint8_t  PortPwrCtrlMask; // just for compatibility, should be 0xff
+} hub_desc_cs_t;
+TU_VERIFY_STATIC(sizeof(hub_desc_cs_t) == 9, "size is not correct");
+TU_VERIFY_STATIC(CFG_TUH_HUB_BUFSIZE >= sizeof(hub_desc_cs_t), "buffer is not big enough");
+
+typedef struct TU_ATTR_PACKED {
+  struct TU_ATTR_PACKED {
+    uint8_t logical_power_switching_mode : 2; // [0..1] gannged or individual power switching
+    uint8_t compound_device              : 1; // [2] hub is part of compound device
+    uint8_t over_current_protect_mode    : 2; // [3..4] global or individual port over-current protection
+    uint8_t tt_think_time                : 2; // [5..6] TT think time
+    uint8_t port_indicator_supported     : 1; // [7] port indicator supported
+  };
+  uint8_t rsv1;
+} hub_characteristics_t;
+TU_VERIFY_STATIC(sizeof(hub_characteristics_t) == 2, "size is not correct");
+
 // data in response of HUB_REQUEST_GET_STATUS, wIndex = 0 (hub)
 typedef struct {
   union{
@@ -143,48 +129,52 @@ typedef struct {
     uint16_t value;
   } status, change;
 } hub_status_response_t;
-
 TU_VERIFY_STATIC( sizeof(hub_status_response_t) == 4, "size is not correct");
 
 // data in response of HUB_REQUEST_GET_STATUS, wIndex = Port num
 typedef struct {
-  union {
+  union TU_ATTR_PACKED {
     struct TU_ATTR_PACKED {
-      uint16_t connection             : 1;
-      uint16_t port_enable            : 1;
-      uint16_t suspend                : 1;
-      uint16_t over_current           : 1;
-      uint16_t reset                  : 1;
+      // Bit 0-4 are for change & status
+      uint16_t connection             : 1; // [0] 0 = no device, 1 = device connected
+      uint16_t port_enable            : 1; // [1] port is enabled
+      uint16_t suspend                : 1; // [2]
+      uint16_t over_current           : 1; // [3] over-current exists
+      uint16_t reset                  : 1; // [4] 0 = no reset, 1 = resetting
 
-      uint16_t                        : 3;
-      uint16_t port_power             : 1;
-      uint16_t low_speed              : 1;
-      uint16_t high_speed             : 1;
-      uint16_t port_test_mode         : 1;
-      uint16_t port_indicator_control : 1;
-      uint16_t TU_RESERVED            : 3;
+      // From Bit 5 are for status only
+      uint16_t rsv5_7                 : 3; // [5..7] reserved
+      uint16_t port_power             : 1; // [8] 0 = port is off, 1 = port is on
+      uint16_t low_speed              : 1; // [9] low speed device attached
+      uint16_t high_speed             : 1; // [10] high speed device attached
+      uint16_t port_test_mode         : 1; // [11] port in test mode
+      uint16_t port_indicator_control : 1; // [12] 0: default color, 1: indicator is software controlled
+      uint16_t TU_RESERVED            : 3; // [13..15] reserved
     };
 
     uint16_t value;
   } status, change;
 } hub_port_status_response_t;
-
 TU_VERIFY_STATIC( sizeof(hub_port_status_response_t) == 4, "size is not correct");
 
-// Clear feature
-bool hub_port_clear_feature (uint8_t hub_addr, uint8_t hub_port, uint8_t feature,
-                             tuh_xfer_cb_t complete_cb, uintptr_t user_data);
+//--------------------------------------------------------------------+
+// HUB API
+//--------------------------------------------------------------------+
+
+// Clear port feature
+bool hub_port_clear_feature(uint8_t hub_addr, uint8_t hub_port, uint8_t feature,
+                            tuh_xfer_cb_t complete_cb, uintptr_t user_data);
 
-// Set feature
-bool hub_port_set_feature   (uint8_t hub_addr, uint8_t hub_port, uint8_t feature,
-                             tuh_xfer_cb_t complete_cb, uintptr_t user_data);
+// Set port feature
+bool hub_port_set_feature(uint8_t hub_addr, uint8_t hub_port, uint8_t feature,
+                          tuh_xfer_cb_t complete_cb, uintptr_t user_data);
 
 // Get port status
-bool hub_port_get_status    (uint8_t hub_addr, uint8_t hub_port, void* resp,
-                             tuh_xfer_cb_t complete_cb, uintptr_t user_data);
+bool hub_port_get_status(uint8_t hub_addr, uint8_t hub_port, void *resp,
+                         tuh_xfer_cb_t complete_cb, uintptr_t user_data);
 
 // Get status from Interrupt endpoint
-bool hub_edpt_status_xfer(uint8_t dev_addr);
+bool hub_edpt_status_xfer(uint8_t daddr);
 
 // Reset a port
 TU_ATTR_ALWAYS_INLINE static inline
@@ -192,13 +182,23 @@ bool hub_port_reset(uint8_t hub_addr, uint8_t hub_port, tuh_xfer_cb_t complete_c
   return hub_port_set_feature(hub_addr, hub_port, HUB_FEATURE_PORT_RESET, complete_cb, user_data);
 }
 
-// Clear Reset Change
+// Clear Port Reset Change
 TU_ATTR_ALWAYS_INLINE static inline
 bool hub_port_clear_reset_change(uint8_t hub_addr, uint8_t hub_port, tuh_xfer_cb_t complete_cb, uintptr_t user_data) {
   return hub_port_clear_feature(hub_addr, hub_port, HUB_FEATURE_PORT_RESET_CHANGE, complete_cb, user_data);
 }
 
+// Get Hub status
+TU_ATTR_ALWAYS_INLINE static inline
+bool hub_get_status(uint8_t hub_addr, void* resp, tuh_xfer_cb_t complete_cb, uintptr_t user_data) {
+  return hub_port_get_status(hub_addr, 0, resp, complete_cb, user_data);
+}
 
+// Clear Hub feature
+TU_ATTR_ALWAYS_INLINE static inline
+bool hub_clear_feature(uint8_t hub_addr, uint8_t feature, tuh_xfer_cb_t complete_cb, uintptr_t user_data) {
+  return hub_port_clear_feature(hub_addr, 0, feature, complete_cb, user_data);
+}
 //--------------------------------------------------------------------+
 // Internal Class Driver API
 //--------------------------------------------------------------------+
@@ -206,13 +206,11 @@ bool hub_init       (void);
 bool hub_deinit     (void);
 bool hub_open       (uint8_t rhport, uint8_t dev_addr, tusb_desc_interface_t const *itf_desc, uint16_t max_len);
 bool hub_set_config (uint8_t dev_addr, uint8_t itf_num);
-bool hub_xfer_cb    (uint8_t dev_addr, uint8_t ep_addr, xfer_result_t event, uint32_t xferred_bytes);
+bool hub_xfer_cb    (uint8_t daddr, uint8_t ep_addr, xfer_result_t event, uint32_t xferred_bytes);
 void hub_close      (uint8_t dev_addr);
 
 #ifdef __cplusplus
  }
 #endif
 
-#endif /* _TUSB_HUB_H_ */
-
-/** @} */
+#endif
diff --git a/src/host/usbh.c b/src/host/usbh.c
index a2994cde7..c7a9a868f 100644
--- a/src/host/usbh.c
+++ b/src/host/usbh.c
@@ -44,6 +44,10 @@
   #define CFG_TUH_INTERFACE_MAX   8
 #endif
 
+enum {
+  USBH_CONTROL_RETRY_MAX = 3,
+};
+
 //--------------------------------------------------------------------+
 // Weak stubs: invoked if no strong implementation is available
 //--------------------------------------------------------------------+
@@ -272,9 +276,10 @@ static struct {
   tuh_xfer_cb_t complete_cb;
   uintptr_t user_data;
 
-  uint8_t daddr;
   volatile uint8_t stage;
+  uint8_t daddr;
   volatile uint16_t actual_len;
+  uint8_t failed_count;
 } _ctrl_xfer;
 
 typedef struct {
@@ -285,7 +290,6 @@ typedef struct {
 CFG_TUH_MEM_SECTION static usbh_epbuf_t _usbh_epbuf;
 
 //------------- Helper Function -------------//
-
 TU_ATTR_ALWAYS_INLINE static inline usbh_device_t* get_device(uint8_t dev_addr) {
   TU_VERIFY(dev_addr > 0 && dev_addr <= TOTAL_DEVICES, NULL);
   return &_usbh_devices[dev_addr-1];
@@ -312,6 +316,15 @@ bool tuh_mounted(uint8_t dev_addr) {
   return dev->configured;
 }
 
+bool tuh_connected(uint8_t daddr) {
+  if (daddr == 0) {
+    return _dev0.enumerating; // dev0 is connected if still enumerating
+  } else {
+    const usbh_device_t* dev = get_device(daddr);
+    return dev && dev->connected;
+  }
+}
+
 bool tuh_vid_pid_get(uint8_t dev_addr, uint16_t *vid, uint16_t *pid) {
   *vid = *pid = 0;
 
@@ -421,7 +434,9 @@ bool tuh_rhport_init(uint8_t rhport, const tusb_rhport_init_t* rh_init) {
 }
 
 bool tuh_deinit(uint8_t rhport) {
-  if (!tuh_rhport_is_active(rhport)) return true;
+  if (!tuh_rhport_is_active(rhport)) {
+    return true;
+  }
 
   // deinit host controller
   hcd_int_disable(rhport);
@@ -467,13 +482,11 @@ bool tuh_task_event_ready(void) {
  * This should be called periodically within the mainloop or rtos thread.
  *
    @code
-    int main(void)
-    {
+    int main(void) {
       application_init();
       tusb_init(0, TUSB_ROLE_HOST);
 
-      while(1) // the mainloop
-      {
+      while(1) { // the mainloop
         application_code();
         tuh_task(); // tinyusb host task
       }
@@ -484,7 +497,9 @@ void tuh_task_ext(uint32_t timeout_ms, bool in_isr) {
   (void) in_isr; // not implemented yet
 
   // Skip if stack is not initialized
-  if (!tuh_inited()) return;
+  if (!tuh_inited()) {
+    return;
+  }
 
   // Loop until there is no more events in the queue
   while (1) {
@@ -618,17 +633,9 @@ static void _control_blocking_complete_cb(tuh_xfer_t* xfer) {
 
 // TODO timeout_ms is not supported yet
 bool tuh_control_xfer (tuh_xfer_t* xfer) {
-  // EP0 with setup packet
-  TU_VERIFY(xfer->ep_addr == 0 && xfer->setup);
-
-  // Check if device is still connected (enumerating for dev0)
+  TU_VERIFY(xfer->ep_addr == 0 && xfer->setup); // EP0 with setup packet
   const uint8_t daddr = xfer->daddr;
-  if (daddr == 0) {
-    TU_VERIFY(_dev0.enumerating);
-  } else {
-    const usbh_device_t* dev = get_device(daddr);
-    TU_VERIFY(dev && dev->connected);
-  }
+  TU_VERIFY(tuh_connected(daddr)); // Check if device is still connected (enumerating for dev0)
 
   // pre-check to help reducing mutex lock
   TU_VERIFY(_ctrl_xfer.stage == CONTROL_STAGE_IDLE);
@@ -636,14 +643,15 @@ bool tuh_control_xfer (tuh_xfer_t* xfer) {
 
   bool const is_idle = (_ctrl_xfer.stage == CONTROL_STAGE_IDLE);
   if (is_idle) {
-    _ctrl_xfer.stage       = CONTROL_STAGE_SETUP;
-    _ctrl_xfer.daddr       = daddr;
-    _ctrl_xfer.actual_len  = 0;
+    _ctrl_xfer.stage        = CONTROL_STAGE_SETUP;
+    _ctrl_xfer.daddr        = daddr;
+    _ctrl_xfer.actual_len   = 0;
+    _ctrl_xfer.failed_count = 0;
 
-    _ctrl_xfer.buffer      = xfer->buffer;
-    _ctrl_xfer.complete_cb = xfer->complete_cb;
-    _ctrl_xfer.user_data   = xfer->user_data;
-    _usbh_epbuf.request    = (*xfer->setup);
+    _ctrl_xfer.buffer       = xfer->buffer;
+    _ctrl_xfer.complete_cb  = xfer->complete_cb;
+    _ctrl_xfer.user_data    = xfer->user_data;
+    _usbh_epbuf.request     = (*xfer->setup);
   }
 
   (void) osal_mutex_unlock(_usbh_mutex);
@@ -657,7 +665,7 @@ bool tuh_control_xfer (tuh_xfer_t* xfer) {
   TU_LOG_BUF_USBH(xfer->setup, 8);
 
   if (xfer->complete_cb) {
-    TU_ASSERT( hcd_setup_send(rhport, daddr, (uint8_t const*) &_usbh_epbuf.request) );
+    TU_ASSERT(hcd_setup_send(rhport, daddr, (uint8_t const *) &_usbh_epbuf.request));
   }else {
     // blocking if complete callback is not provided
     // change callback to internal blocking, and result as user argument
@@ -667,7 +675,7 @@ bool tuh_control_xfer (tuh_xfer_t* xfer) {
     _ctrl_xfer.user_data   = (uintptr_t) &result;
     _ctrl_xfer.complete_cb = _control_blocking_complete_cb;
 
-    TU_ASSERT( hcd_setup_send(rhport, daddr, (uint8_t*) &_usbh_epbuf.request) );
+    TU_ASSERT(hcd_setup_send(rhport, daddr, (uint8_t *) &_usbh_epbuf.request));
 
     while (result == XFER_RESULT_INVALID) {
       // Note: this can be called within an callback ie. part of tuh_task()
@@ -724,28 +732,46 @@ static bool usbh_control_xfer_cb (uint8_t daddr, uint8_t ep_addr, xfer_result_t
   const uint8_t rhport = usbh_get_rhport(daddr);
   tusb_control_request_t const * request = &_usbh_epbuf.request;
 
-  if (XFER_RESULT_SUCCESS != result) {
-    TU_LOG_USBH("[%u:%u] Control %s, xferred_bytes = %" PRIu32 "\r\n", rhport, daddr, result == XFER_RESULT_STALLED ? "STALLED" : "FAILED", xferred_bytes);
-    TU_LOG_BUF_USBH(request, 8);
+  switch (result) {
+    case XFER_RESULT_STALLED:
+      TU_LOG_USBH("[%u:%u] Control STALLED, xferred_bytes = %" PRIu32 "\r\n", rhport, daddr, xferred_bytes);
+      TU_LOG_BUF_USBH(request, 8);
+      _control_xfer_complete(daddr, result);
+    break;
 
-    // terminate transfer if any stage failed
-    _control_xfer_complete(daddr, result);
-  }else {
-    switch(_ctrl_xfer.stage) {
-      case CONTROL_STAGE_SETUP:
-        if (request->wLength) {
-          // DATA stage: initial data toggle is always 1
-          _set_control_xfer_stage(CONTROL_STAGE_DATA);
-          TU_ASSERT( hcd_edpt_xfer(rhport, daddr, tu_edpt_addr(0, request->bmRequestType_bit.direction), _ctrl_xfer.buffer, request->wLength) );
-          return true;
-        }
+    case XFER_RESULT_FAILED:
+      if (tuh_connected(daddr) && _ctrl_xfer.failed_count < USBH_CONTROL_RETRY_MAX) {
+        TU_LOG_USBH("[%u:%u] Control FAILED %u/%u, retrying\r\n", rhport, daddr, _ctrl_xfer.failed_count+1, USBH_CONTROL_RETRY_MAX);
+        (void) osal_mutex_lock(_usbh_mutex, OSAL_TIMEOUT_WAIT_FOREVER);
+        _ctrl_xfer.stage = CONTROL_STAGE_SETUP;
+        _ctrl_xfer.failed_count++;
+        _ctrl_xfer.actual_len = 0; // reset actual_len
+        (void) osal_mutex_unlock(_usbh_mutex);
+
+        TU_ASSERT(hcd_setup_send(rhport, daddr, (uint8_t const *) request));
+      } else {
+        TU_LOG_USBH("[%u:%u] Control FAILED, xferred_bytes = %" PRIu32 "\r\n", rhport, daddr, xferred_bytes);
+        TU_LOG_BUF_USBH(request, 8);
+        _control_xfer_complete(daddr, result);
+      }
+    break;
+
+    case XFER_RESULT_SUCCESS:
+      switch(_ctrl_xfer.stage) {
+        case CONTROL_STAGE_SETUP:
+          if (request->wLength) {
+            // DATA stage: initial data toggle is always 1
+            _set_control_xfer_stage(CONTROL_STAGE_DATA);
+            TU_ASSERT( hcd_edpt_xfer(rhport, daddr, tu_edpt_addr(0, request->bmRequestType_bit.direction), _ctrl_xfer.buffer, request->wLength) );
+            return true;
+          }
         TU_ATTR_FALLTHROUGH;
 
-      case CONTROL_STAGE_DATA:
-        if (request->wLength) {
-          TU_LOG_USBH("[%u:%u] Control data:\r\n", rhport, daddr);
-          TU_LOG_MEM_USBH(_ctrl_xfer.buffer, xferred_bytes, 2);
-        }
+        case CONTROL_STAGE_DATA:
+          if (request->wLength) {
+            TU_LOG_USBH("[%u:%u] Control data:\r\n", rhport, daddr);
+            TU_LOG_MEM_USBH(_ctrl_xfer.buffer, xferred_bytes, 2);
+          }
 
         _ctrl_xfer.actual_len = (uint16_t) xferred_bytes;
 
@@ -754,23 +780,26 @@ static bool usbh_control_xfer_cb (uint8_t daddr, uint8_t ep_addr, xfer_result_t
         TU_ASSERT( hcd_edpt_xfer(rhport, daddr, tu_edpt_addr(0, 1 - request->bmRequestType_bit.direction), NULL, 0) );
         break;
 
-      case CONTROL_STAGE_ACK: {
-        // Abort all pending transfers if SET_CONFIGURATION request
-        // NOTE: should we force closing all non-control endpoints in the future?
-        if (request->bRequest == TUSB_REQ_SET_CONFIGURATION && request->bmRequestType == 0x00) {
-          for(uint8_t epnum=1; epnum<CFG_TUH_ENDPOINT_MAX; epnum++) {
-            for(uint8_t dir=0; dir<2; dir++) {
-              tuh_edpt_abort_xfer(daddr, tu_edpt_addr(epnum, dir));
+        case CONTROL_STAGE_ACK: {
+          // Abort all pending transfers if SET_CONFIGURATION request
+          // NOTE: should we force closing all non-control endpoints in the future?
+          if (request->bRequest == TUSB_REQ_SET_CONFIGURATION && request->bmRequestType == 0x00) {
+            for(uint8_t epnum=1; epnum<CFG_TUH_ENDPOINT_MAX; epnum++) {
+              for(uint8_t dir=0; dir<2; dir++) {
+                tuh_edpt_abort_xfer(daddr, tu_edpt_addr(epnum, dir));
+              }
             }
           }
+
+          _control_xfer_complete(daddr, result);
+          break;
         }
 
-        _control_xfer_complete(daddr, result);
-        break;
+        default: return false; // unsupported stage
       }
+      break;
 
-      default: return false;
-    }
+    default: return false; // unsupported result
   }
 
   return true;
@@ -891,7 +920,6 @@ bool usbh_edpt_release(uint8_t dev_addr, uint8_t ep_addr) {
 }
 
 // Submit an transfer
-// TODO call usbh_edpt_release if failed
 bool usbh_edpt_xfer_with_callback(uint8_t dev_addr, uint8_t ep_addr, uint8_t* buffer, uint16_t total_bytes,
                                   tuh_xfer_cb_t complete_cb, uintptr_t user_data) {
   (void) complete_cb;
@@ -1657,7 +1685,7 @@ static bool _parse_configuration_descriptor(uint8_t dev_addr, tusb_desc_configur
     if ( 0 == tu_desc_len(p_desc) ) {
       // A zero length descriptor indicates that the device is off spec (e.g. wrong wTotalLength).
       // Parsed interfaces should still be usable
-      TU_LOG_USBH("Encountered a zero-length descriptor after %u bytes\r\n", (uint32_t)p_desc - (uint32_t)desc_cfg);
+      TU_LOG_USBH("Encountered a zero-length descriptor after %" PRIu32 "bytes\r\n", (uint32_t)p_desc - (uint32_t)desc_cfg);
       break;
     }
 
@@ -1771,8 +1799,9 @@ static void enum_full_complete(void) {
   _dev0.enumerating = 0;
 
 #if CFG_TUH_HUB
-  // get next hub status
-  if (_dev0.hub_addr) hub_edpt_status_xfer(_dev0.hub_addr);
+  if (_dev0.hub_addr) {
+    hub_edpt_status_xfer(_dev0.hub_addr); // get next hub status
+  }
 #endif
 
 }
diff --git a/src/host/usbh.h b/src/host/usbh.h
index 72c237573..c8b137173 100644
--- a/src/host/usbh.h
+++ b/src/host/usbh.h
@@ -183,6 +183,10 @@ tusb_speed_t tuh_speed_get(uint8_t daddr);
 // Check if device is connected and configured
 bool tuh_mounted(uint8_t daddr);
 
+// Check if device is connected which mean device has at least 1 successful transfer
+// Note: It may not be addressed/configured/mounted yet
+bool tuh_connected(uint8_t daddr);
+
 // Check if device is suspended
 TU_ATTR_ALWAYS_INLINE static inline
 bool tuh_suspended(uint8_t daddr) {
diff --git a/src/host/usbh_pvt.h b/src/host/usbh_pvt.h
index 95de915e9..d27c4baa2 100644
--- a/src/host/usbh_pvt.h
+++ b/src/host/usbh_pvt.h
@@ -83,8 +83,8 @@ void usbh_defer_func(osal_task_func_t func, void *param, bool in_isr);
 bool usbh_edpt_xfer_with_callback(uint8_t dev_addr, uint8_t ep_addr, uint8_t * buffer, uint16_t total_bytes,
                                   tuh_xfer_cb_t complete_cb, uintptr_t user_data);
 
-TU_ATTR_ALWAYS_INLINE
-static inline bool usbh_edpt_xfer(uint8_t dev_addr, uint8_t ep_addr, uint8_t * buffer, uint16_t total_bytes) {
+TU_ATTR_ALWAYS_INLINE static inline
+bool usbh_edpt_xfer(uint8_t dev_addr, uint8_t ep_addr, uint8_t * buffer, uint16_t total_bytes) {
   return usbh_edpt_xfer_with_callback(dev_addr, ep_addr, buffer, total_bytes, NULL, 0);
 }