Linux/CC2564: A2DP audio is completely distorted since connected

Will Liao

Intellectual 540 points

Part Number: CC2564

Tool/software: Linux

We found A2DP audio may be completely distorted since connected, and it will not recover back unless re-connection.

Here is the step to reproduce this issue:

Phone initiates pairing to unit
Start A2DP streaming

The attachment is the HCI trace, please check the extracted A2DP audio. It is not easy to collect the air trace, do you need TI firmware log?

https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/538/8132.hci_5F00_dump.7z

We also found the issue can not be reproduced while CC2564 is master.

over 6 years ago

0 S over 6 years ago

TI__Mastermind 35795 points

Hi ,
Can you pls provide more details - Host MCU , firmware logs ?

Thanks
Saurabh

0 Will Liao over 6 years ago in reply to S

Intellectual 540 points

Sure, we are using ARM based processor - Cortex A7.

We reproduced this issue with Samsung S8 and got the HCI trace on phone side, the HCI trace shows the distorted A2DP audio is coming from phone side:

/cfs-file/__key/communityserver-discussions-components-files/538/btsnoop_5F00_hci_5F00_201902121213_5F00_from_5F00_s8.zip

Here is the firmware log:

/cfs-file/__key/communityserver-discussions-components-files/538/CC2564_5F00_A2DP.zip

And we found a easy way to reproduce this issue:

1. DUT starts inquiry

2. Phone initiates pair to DUT

3. DUT starts streaming A2DP

0 Vihang Parmar over 6 years ago in reply to Will Liao

TI__Mastermind 29291 points

Hi Will,

The ACL connection in the logs is kept to the default "Best effort" service-type. When an ACL connection is best effort, other high priority activities like the connection procedure or inquiry can cause lower throughput. For A2DP type of application, this may result in choppy audio. It is best to update the QoS and change the service type to "Guaranteed" for A2DP use-case to raise the priority of the ACL connection.

Please refer to the "QoS Setup" section of the Bluetooth specification for the commands required to change the service type of an ACL connection.

Best regards,
Vihang

0 Will Liao over 6 years ago in reply to Vihang Parmar

Intellectual 540 points

Hi Vihang,

Sorry for the late reply.

I changed the ACL connection to "Guaranteed" after A2DP/AVRCP connected, but it seems not working for this issue. Please check the attached HCI trace and firmware log, and frame #352 is the link policy command with "Guaranteed" service type.

/cfs-file/__key/communityserver-discussions-components-files/538/Log_5F00_1.zip

0 Will Liao over 6 years ago in reply to Will Liao

Intellectual 540 points

Can I have your update? Thanks.

Bluetooth®︎

Bluetooth forum

Linux/CC2564: A2DP audio is completely distorted since connected