delayed suspend_evt in a2dp sink app.

[bemale]

Hello,

I found that there is long delay time for around 10 secs to be displayed trace message below

[a2dp_sink_control_cback] Event: (4) WICED_BT_A2DP_SINK_SUSPEND_EVT

after I stop a music in my smartphone(iPhone12).

I think smartphone sends a suspend signal to CYW920706 immediately, but the Event IND is stuck in some timer function in BT stack.

Could you let me know if this is normal operation or do you have any patch to improve the delay time?

thanks.

[bemale]

Hi SheetalJ,

I've been tested again it with Android phone and found it took just 4secs. interesting!! means that the delay time of "suspend_ind" event depends on OS type.  Anyhow, I also found the audio steaming was stopped immediately regardless display of the suspend evt. I'm not a BT engineer, so couldn't understand the technical procedure between phone and your wireless chip but expected that it's prompted to serial terminal at that time immediately.

I assumed that the IND signal will be sent to the BT stack of CYW20706 from BT stack of a phone over the air, then it should be processed within a millisecond latency. Do I need to look into some time out values defined in your AVDTP protocol side to understand this phenomenon?

For your question, I'm using Modus ToolBox currently as your recommendation at the beginning.

Thanks.

[SheetalJ · Accepted solution]

Your assumption is correct. The indication should reach within milliseconds to the device. As per my understanding, there is no value set as such for notification-indication communication. Its normal GATT operation. Maybe we will need to look at air logs to debug this issue further. 

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