linux - Can not connect to BLE device from Android 4.4.2 -

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i developing system there 2 application: first application on android, second application run on linux. must communicate via ble protocol

on linux, have modified code of bluez 4.1(btgattserver.c). application on linux broadcast ble advertiser package, , wait connect android.

on android, using api connect linux application:

public bluetoothgatt connectgatt (context context, boolean autoconnect, bluetoothgattcallback callback)

my problem is: on android 5, these applications can communicate normally. on android 4.4.2, android application can not connect linux application

i have turned on option "enable bluetooth hci snoop" on android , got log file of hci on android 5. , android 4.4.2 compare.

i found on android 5., request connect has psm sdp, request connect on android 4.4.2 has psm att. , connection on android 4.4.2 rejected linux application (please see attached image) enter image description here please tell why android 4.4.2 create connect request psm att? , how resolve problem?

because english not good, im sorry if question make difficult understand.

thanks you.


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