Cannot send BULK vendor response (rp2040)

[GiantNuker]

I'm trying to send a bulk transfer in response to a control transfer. So far I've managed to send and recieve a control and bulk transfer from the host, however I cannot send the transfer from the device.
In the following example, The Bulk xfer line should say OK and the Write buffer line should be back at 64 on the second time i run refresh.

simplescreenrecorder-2021-03-04_17.48.08.mp4

From what I can tell, The transfer never happens, as the write buffer size dosen't return to 64. Since usb is based on the host polling the device, first I tried running something else on the device, with very similar host code. It worked perfectly fine using The Pi Pico low level usb example when I sent a 64 byte array to it, and it repeated it back. However when I used tud_vendor_n_write_str I wasn't able to recieve the bulk response.
The relevant host code:

void refreshConnection() {
    log_message("Refreshing...");

    libusb_device** device_list;
    ssize_t device_count = libusb_get_device_list(NULL, &device_list);
    if (device_count < 0) {
        char resp[100] = "Failed to get device list: ";
        strcpy(resp + 26, libusb_error_name(device_count));
        log_message(resp);
        return;
    }

    for (ssize_t i = 0; i < device_count; i++) {
        struct libusb_device_descriptor desc;
		int r = libusb_get_device_descriptor(device_list[i], &desc);
		if (r < 0) {
			log_message("Failed to get device descriptor");
            continue;
		}

        if (desc.idVendor == 0x1337 && desc.idProduct == 0x400a) {
            log_message("Found keyboard");
            libusb_device_handle* device_handle = NULL;
            libusb_open(device_list[i], &device_handle);
            if (device_handle != 0) {
                log_message("Opened keyboard");
                int r = libusb_claim_interface(device_handle, 2);
                if (r != 0) {
                    char resp[100] = "Failed to claim interface: ";
                    strcpy(resp + 27, libusb_error_name(r));
                    log_message(resp);
                    continue;
                }
                r = libusb_control_transfer(device_handle, 0x41, 0x01, 0, 0, NULL, 0, 1000);
                char resp[100] = "Control xfer: ";
                if (r < 0) {
                    strcpy(resp + 14, libusb_error_name(r));
                } else {
                    strcpy(resp + 14, "OK");
                }
                log_message(resp);
                uint8_t buffer[64] = {0};
                memset(buffer, 0x69, 62);
                int buffer_len = 64;
                r = libusb_bulk_transfer(device_handle, 0x8f, buffer, 64, &buffer_len, 1000);
                char resp2[164] = "Bulk xfer: ";
                if (r < 0) {
                    strcpy(resp2 + 11, libusb_error_name(r));
                } else {
                    strcpy(resp2 + 11, "OK: ");
                }
                log_message(resp2);

                libusb_close(device_handle);
                //todo
            } else {
                log_message("Unable to open keyboard");
            }
        } else {
            // char msg[100] = "Found non-keyboard: ";
            // sprintf(msg + 20, "VID: %04x PID: %04x", desc.idVendor, desc.idProduct);
            // log_message(msg);
        }
    }

    libusb_free_device_list(device_list, 1);
}

The relevant device code:

bool tud_vendor_control_request_cb(uint8_t rhport, tusb_control_request_t const * request) {
    switch (request->bRequest) {
        case 0x01:
            gpio_put(PIN_LED3, true);
            printf("Aight\n");
            printf("Write buffer size: %d\n", tud_vendor_n_write_available(USB_VENDOR_DEBUG_N));
            tud_vendor_n_write_str(USB_VENDOR_DEBUG_N, "respondssssseee!");
            printf("Write buffer size: %d\n", tud_vendor_n_write_available(USB_VENDOR_DEBUG_N));
            return tud_control_status(rhport, request);
        default:
            return false;
    }
}

Anyone have a clue?
I looked at the webusb example and picoprobe, which both appear to use it exactly the same way without any issues.

• Yes I have made sure I'm using the correct interfaces/endpoints (I checked all of them just to be sure)
• Yes tud_task() is being called

[hathach]

try to build tinyusb with CFG_TUSB_DEBUG=2 and have your printf() output to uart, then post the tinyusb debug log here. I could have a hint where thing failed. Also make sure you build with tinyusb latest code, there are lots of fixes lately for rp2040 port.

[hathach]

FYI #609 #645 or #646

[GiantNuker]

@hathach just commnted the flag and it stopped working; CFG_TUSB_DEBUG=2 fixes the issue though.

[hathach]

You seem to have incorrect conifg descriptor the log show endpoint 0x8f which is a bit odd.

[GiantNuker]

0x8f is intentional, that way I can add more interfaces without having to rearrange the debug one so its last.

[hathach]

If you are on Linux, try to update udev rules accordinly #710 . Other than that i don't see any other issues in your log. It is probably due to your own firmware implementation, try to throw a bit of printf() and step through the program to troubleshoot. Keep updating this thread if you figure out something, maybe other with similar set up could help.