zephyr: esp32-usb-serial tx-complete interrupt not working in interrupt mode on esp32c3

Describe the bug Hi! I’m running into some issue when trying to use the usb_serial device on an ESP32C3 system. When running the shell_module sample, I can tell that the data is received correctly, but the output buffer is only flushed as a reaction to a receive event. For example I can type a command, but the echo is delayed and the output is not printed until something else is sent on the serial port. The behavior seems to indicate that serial_esp32_usb_isr is not being called as it should when the transmit buffer is empty, hence stopping the application from flushing its transmit queue.

The driver works correctly in polling mode (CONFIG_SHELL_BACKEND_SERIAL_INTERRUPT_DRIVEN=n).

Additionally, the USB debug interface fails entirely when building the wifi sample (that is, does not enumerate, errors in dmesg, have to reset it in bootloader mode to flash it again). Could this be some interrupt management issue?

Disclaimer: I’m actually using a Seeed XIAO-ESP32-C3 board, not the official esp32c3_devkitm, but I think the problem should be the same since the device is builtin.

To Reproduce Steps to reproduce the behavior:

patch boards/riscv/esp32c3_devkitm/esp32c3_devkitm.dts

-               zephyr,shell-uart = &uart0;
+               zephyr,shell-uart = &usb_serial;

build and flash the shell_module sample

west build -p -b esp32c3_devkitm samples/subsys/shell/shell_module
west flash

access the shell interface (minicom, west espressif monitor…), send some command, output is not flushing
build and flash with west build -p -b esp32c3_devkitm samples/subsys/shell/shell_module -DCONFIG_SHELL_BACKEND_SERIAL_INTERRUPT_DRIVEN=y, the shell works fine

Expected behavior The USB serial works as expected.

Impact Annoyance

Environment (please complete the following information):

Linux, Zephyr SDK 0.15.2, main (55843e7d77), Seeed XIAO-ESP32-C3

About this issue

Original URL
State: closed
Created 2 years ago
Reactions: 1
Comments: 16 (9 by maintainers)

Most upvoted comments

@fabiobaltieri, The below has been fixed already, but needs west.yml update, which depends of other PRs).

Additionally, the USB debug interface fails entirely when building the wifi sample (that is, does not enumerate, errors in dmesg, have to reset it in bootloader mode to flash it again). Could this be some interrupt management issue?

I was able to confirm the same issue, will take a look. Thanks!

sylvioalves on Nov 30, 2022

Also confirmed it works, thanks.

sylvioalves on Mar 29, 2023

Calling irq callback after enabling tx interrupt fixed this issue for me.

Hey that did it, mind sending a PR with the change? https://docs.zephyrproject.org/latest/contribute/guidelines.html#contribution-guidelines

fabiobaltieri on Mar 29, 2023

Calling irq callback after enabling tx interrupt fixed this issue for me.

static void serial_esp32_usb_irq_tx_enable(const struct device *dev)
{
    struct serial_esp32_usb_data *data = dev->data;

    usb_serial_jtag_ll_clr_intsts_mask(USB_SERIAL_JTAG_INTR_SERIAL_IN_EMPTY);
    usb_serial_jtag_ll_ena_intr_mask(USB_SERIAL_JTAG_INTR_SERIAL_IN_EMPTY);

    if (data->irq_cb != NULL) {
        data->irq_cb(dev, data->irq_cb_data);
    }
}

horakdavid on Mar 29, 2023