After NCS 1.3.0 nRF Desktop LLPM is disconnected, there is no data on the USB.

[helen]

I now integrate USB, BLE, LLPM, keyboard HID and Mouse HID to nrf52833.

When I added CONFIG_DESKTOP_HID_MOUSE=y, my project was abnormal.

BLE connection:                     Move Mouse and report keyboard work correctly.

USB connected:                      data cannot be reported to PC.

LLPM cannot be connected:   disconnect after connection, and then repeat the process.

[Kenneth]

Hello,

Have you tried the latest v1.4.1 release?

Kenneth

[helen]

I tried for a few days and still couldn’t achieve the desired effect. I made the following changes:

1. usb_state.c

1.1 Modify usb_init usb_hid_device[1] as KEYBOARD and usb_hid_device[0] as MOUSE.

        usb_hid_device[0].dev = device_get_binding("HID_0");
	if (usb_hid_device[0].dev == NULL) {
		LOG_ERR("Cannot get USB HID 0 Device");
		return 0;
	}

	usb_hid_register_device(usb_hid_device[0].dev, hid_mouse_report_desc,   // hid_kbd_report_desc   hid_mouse_report_desc
				sizeof(hid_mouse_report_desc),&hid_ops[0]);

	usb_hid_init(usb_hid_device[0].dev);


	usb_hid_device[1].dev = device_get_binding("HID_1");
	if (usb_hid_device[1].dev == NULL) {
		LOG_ERR("Cannot get USB HID 1 Device");
		return 0;
	}

	usb_hid_register_device(usb_hid_device[1].dev, hid_mouse_report_desc,
				sizeof(hid_mouse_report_desc),&hid_ops[1]);

	usb_hid_init(usb_hid_device[1].dev);

2.hid_static.c

#define SUBSCRIBER_COUNT (IS_ENABLED(CONFIG_DESKTOP_HIDS_ENABLE) + \
              IS_ENABLED(CONFIG_DESKTOP_USB_ENABLE)+IS_ENABLED(CONFIG_DESKTOP_USB_ENABLE))

Modify hid_state struct to add an additional subscriber for usb_hid_device[1] (KEYBOARD).

struct hid_state {
    struct report_data report_data[INPUT_REPORT_DATA_COUNT];
    struct subscriber subscriber[SUBSCRIBER_COUNT];
    struct subscriber *selected;
        struct subscriber *selected_extra;//！！
};

handle_usb_hid_event｛
    if (event->enabled) {
        //if (!get_subscriber_by_type(true)) { //Multiple USB subscribers can be added
            connect_subscriber(event->id, true, 1);
        //}
    } else {
        disconnect_subscriber(event->id);
    }
｝

Assign the subscriber of MOUSE to state.selected KEYBOARD to state.selected_extra

connect_subscriber｛

static uint8_t usb_count = 0; // sean 1.6
  usb_count++;// sean 1.6
//				for (size_t j = 0; j < ARRAY_SIZE(state.report_data); j++) { //sean 1.6
//					struct report_data *rd = &state.report_data[j];
//
//					rd->linked_rs = NULL;
//					clear_report_data(rd);
//				}
                                  if(usb_count==1)
				state.selected = NULL;
                             
			}
                     
            if(usb_count == 2)
                  state.selected_extra = &state.subscriber[i];

			if (!state.selected ) {

                          if(usb_count==1)
                          {
                          state.selected = &state.subscriber[i];
                          LOG_INF("!! Active subscriber %p %d",state.selected->id,i);
                          }

			}
			...
｝

Used state.selected_extra at the time of sending keyboard report

send_report_keyboard
{
   ... 
    event->subscriber = state.selected_extra->id;
}
​
report_send{
    ....
     __ASSERT_NO_MSG(rs->subscriber == state.selected || rs->subscriber == state.selected_extra);
     
     
｝
     

Press the mouse, the mouse responds.

You can see that the code is executed to hid_int_ep_write

LOG print

usb_hid->dev = 0x20000f18; usb_hid_device[1].dev = 0x20000f00

Note: usb_hid_device[0].dev = 0x20000f18 (MOUSE)

Press the keyboard, No characters output on PC ！！！

LOG print

usb_hid->dev = 0x20000f00; usb_hid_device[1].dev = 0x20000f00

Note: usb_hid_device[1].dev = 0x20000f00 (KEYBOARD)

But report_sent_cb is not executed.

I tried many methods and I don't know how to modify it!

[Kenneth]

Combining mouse and keyboard is something that we have "missed" in ncs1.3, we have added the functionality to ncs1.4.0. In general the problem is in hid_state - we have assumed all reports will go to "separate" transports (by separate I mean each handling its own state).
​
The problem with usb in ncs1.3.0 is that it can send only one report at a time so there is no way you can send both mouse and keyboard report as hid_state will not know how to handle it.
​
I believe this fix may have been backported to ncs1.3 - you can see the backported changes here:
https://github.com/pdunaj/fw-nrfconnect-nrf/commits/DESK-1072 

What you are interested in is:
https://github.com/pdunaj/fw-nrfconnect-nrf/commit/e4cf5d2af1f626d5e35ad0fc1ec0124996c63fd1 

I recommend to have a look at all the changes - because some are fixing report descriptors to make them compliant. After you apply the fix the only thing needed to have mouse + keyboard reports on one peripheral device would be to enable these reports in kconfig.
​
There is however one thing to know - we still don't support multiple usb hid class instances for peripheral. That is hid_state will NOT handle this situation right and we believe this was the problem that you were experiencing when trying out ncs1.4.0.
​
Since there is all the code needed (I believe) to redirect reports (in hid_state) to different instances of USB HID class, this should be doable, but you still you have to add some logic to correctly select which instance to use as a selected subscriber for a given report.