DWC2 Host Stack Fails to Detect Device Removal Due to HPRT_CONN_DETECT

[nickfox-taterli]

Operating System

Linux

Board

STM32L4R5 Nucleo-144,STM32F412 Nucleo-144

Firmware

When the host stack is activated, it always happens.

Tested with GCC, IAR, Keil.

gcc version 13.3.1 20240614 (Arm GNU Toolchain 13.3.Rel1 (Build arm-13.24))

What happened ?

I've encountered an issue with the DWC2 Host stack where device removal events are not correctly detected. This problem arises because the HPRT_CONN_DETECT bit in the hprt register is not set when the conn_status changes from 1 to 0. As a result, the hcd_event_device_remove function is not called, leaving the system unaware that a device has been disconnected.

How to reproduce ?

1. Connect a USB device to the host port.
2. Observe that the device is correctly detected and hcd_event_device_attach is called.
3. Disconnect the USB device.
4. Notice that hcd_event_device_remove is not triggered because dwc2->hprt & HPRT_CONN_DETECT remains unset, even though hprt_bm.conn_status changes to 0.

My temporary solution:

static void handle_hprt_irq(uint8_t rhport, bool in_isr)
{
  dwc2_regs_t *dwc2 = DWC2_REG(rhport);
  uint32_t hprt = dwc2->hprt & ~HPRT_W1_MASK;
  const dwc2_hprt_t hprt_bm = dwc2->hprt_bm;

  // Static array to store the previous connection status of each rhport
  static bool previous_conn_status[2] = {false};

  // Get the current connection status
  bool current_conn_status = hprt_bm.conn_status;

  // Check if HPRT_CONN_DETECT interrupt is set
  if (dwc2->hprt & HPRT_CONN_DETECT)
  {
    // ...
  }

  // Handle case where HPRT_CONN_DETECT is not set but conn_status has changed
  if (previous_conn_status[rhport] && !current_conn_status)
  {
    // Connection status changed from 1 to 0, call device remove
    hcd_event_device_remove(rhport, in_isr);
  }

  // Update the previous connection status
  previous_conn_status[rhport] = current_conn_status;

  // ...
}

Debug Log as txt file (LOG/CFG_TUSB_DEBUG=2)

When plugging and unplugging the device several times it stops exactly at this assertion, which LOG observes precisely because the device did not perform a removal before.

static bool enum_request_set_addr(void) {
  tusb_desc_device_t const* desc_device = (tusb_desc_device_t const*) _usbh_epbuf.ctrl;

  // Get new address
  uint8_t const new_addr = get_new_address(desc_device->bDeviceClass == TUSB_CLASS_HUB);
  TU_ASSERT(new_addr != 0);
  TU_LOG_USBH("Set Address = %d\r\n", new_addr);

  // ....
}

Screenshots

No response

I have checked existing issues, dicussion and documentation

• I confirm I have checked existing issues, dicussion and documentation.