Is it possible to change hid descriptor dynamically after Softreset with the same bonded device?

[JackyYuen]

Currently, other device can only re bond with my device to change the hid descriptor, is it possible to directly update the cached hid descriptor?

[Edvin]

Hello,

I would expect it to be possible, from a Bluetooth perspective, but since you are asking, it sounds like you will have issues when the operating system of the connected device doesn't detect the change before you re bond. 

Can you please try to capture a sniffer trace and see if the data on air is actually updated?

Why do you need to change it by the way? I don't think it is a common use-case in a final product?

Best regards,

Edvin

[JackyYuen]

I was no luck trying out the nrf sniffer with wireshark, it seems cannot find the port for the sniffer dongle, the images shows that the hid report map is changed. However, I am having difficulties with device running with operating system like windows. The hid desciptor map is not updated, and result in only operational while the device is in the same mode with that when it is paired with the system.

[Edvin]

Ok, so if you see the change using nRF Connect for Desktop -> Bluetooth Low Energy, then you verify that the HID descriptor is in fact changed. 

That also suggests that the issue lies with the OS. 

From a HID over USB perspective, this "makes sense" as a device is not allowed to update it's USB descriptor, which means it can't update it's HID over USB descriptor. 

In some sense, it makes sense that you typically wouldn't do a firmware upgrade which gives your HID Keyboard a new button. The descriptor wouldn't typically change during the lifetime of a product.

Is this the case for you? You need to roll out an update which requires an update to the HID descriptor?

Best regards,

Edvin

[JackyYuen]

I need the device to be using different HID descriptor such as mouse,keyboard and controller based on the mode that user selected, currently it works after re pairing the device with the OS.

[Edvin]

How about including all of it in the HID report, but just utilizing one at the time? That is how I imagine something like that would need to be set up.

Best regards,

Edvin