HID reconnection problem

[David]

I'm trying to save power on my HID keyboard application by disconnecting the Bluetooth link after some time of inactivity. As soon as there are keystrokes to send, the device advertises again and sends the pending values.

Generally I have 8 chars to transmit at once, but in Android 7.1.1 (Nexus 5X) I often get only 7 or less. The first one or two characters seem to get lost, although there is no error event generated by my nRF8001. I even get the right number of data credit events, so I assume the values have been sent correctly. The second value (again 8 chars) is always transmitted entirely.

I always wait for the first pipe status event after reconnection, sending data right after the connected event makes it even worse.

How can I achieve a reliable transmission of my first value? Is there some event to tell me that the master device is fully ready to receive keystrokes? Has someone experienced a similar behaviour and found a workaround?

[David]

Yes, I use a bonded connection. The first pipe status event shows that all previously opened pipes are still available. When sending keystrokes directly after the connected event, there are even more devices that do not display all of them. An iPad mini with iOS8.1 misses my first 2 or 3 characters, the Nexus 5X even up to 5 chars...

For information: All the tests are done with the Nordic ble_HID_keyboard_template.

I have an nRF51822 dongle (PCA10000) that should work as a sniffer, but I can't get it to work. Is there an updated version that would work with the actual version of wireshark (2.2.5)?