LLPM questions

[Hannibalhz]

Dear Nordic Engineer

Our costomer has developed a keyboard using LLPM in NCS.Now Now they have encountered some problems.We have been working with them for a long time but there still no good solution to these problems.

1、When using the WIN 10 Version 20H2 or higher the PC will be connected to the keyboard.After working for a period of time the Caps and Num indicator lights will not light up.Our research found that the reason is that the PC did't issue instuctions to the keyboard.In this case,the "keyboard_leds_handler"  does not resond.Because the communication data encrtpted we can't capture the data packet,so this problem is shelved and we can't solve it.

2、 In wired mode, the keyboard uses a USB cable to connect to the PC.The keyboard can't wake up the PC while it's sleeping.Our research found that when the PC is sleeping,we call "usb_wakeup => usb_wakeup_request"  and the D+ line of the USB will generate a signal.We measured the duration an oscilloscope to be about 10ms, but this did not wake the PC.

Please give us some good suggestions.

Best regard.

[Kenneth]

I have reported it internally, let me know if you have further findings to the issues that I can add internally.

Kenneth

[Kenneth]

Hi,

Regarding 1. I do believe customer is in contact with one of our FAE's on these issues, is that right?

Regarding 2.

We've tested with ncs 1.6.1 release and build for nrf52840dk_nrf52840, app_ZDebug.conf. Before the HOST PC is going to sleep it has to enable the remote wakeup feature - that could be disabled by default in bios. We did not see any bug there, please correct me if we do not test it as the customer does. Please see below LOG output.

...
00> [03607907] <dbg> usb_device.usb_handle_std_device_req: REQ_SET_FEATURE
00> [03608012] <inf> usb_hid: Device suspended
00> [03608013] <wrn> usb_state: USB suspend
00> [03608014] <inf> usb_state: USB HID 0x20003074 disabled
...
00> [03608020] <inf> event_manager: e: usb_state_event state:SUSPENDEDI'm not sure if i got it correctly
...
00> [04005444] <inf> event_manager: e: button_event key_id=0x3 pressed
00> [04005460] <inf> usb_hid: Device resumed

Best regards,
Kenneth