[Bug Report] Severe A/V Sync Deadlock & Audio Drop with Intel BT Driver 24.20.0.3

[Lostinspace]

This bug happened when I was using my Galaxy Book 5 pro and S25+ phone, and S9 Ultra tablet. and when autoswitch happened(or manual) from phone -> laptop or tablet -> laptop BT connection did happen but sound never cameout.

Notification: This report is made by help of the ai because I am not that good at English.

Hello, I am reporting a critical compatibility bug and bandwidth throttling issue introduced in the latest Intel Wireless Bluetooth Driver (v24.20.0.3). When using multipoint Bluetooth connections (specifically Samsung Galaxy Buds2 Pro with 'Auto Switch' feature enabled across PC, Tablet, and Phone), the v24.20.0.3 driver causes a complete audio routing failure and A/V sync deadlock on Windows 11.

System Environment:

• OS: Windows 11

• Device: Samsung Galaxy Buds2 Pro

• Trigger Condition: Samsung "Auto Switch" (Continuity Service) active across multiple devices (May related to Heavy Bluetooth LE background pinging).

Symptoms (with v24.20.0.3):

1. Audio Drop & Deadlock: Windows claims the Bluetooth device is connected, but no sound is outputted.

2. Browser Pipeline Destroyed: Chromium-based browsers (Chrome/Edge) suffer infinite buffering on YouTube. The browser's Media Internals show State: Destroyed and missing audio decoders due to the driver failing to establish an audio channel (A2DP).

3. No Windows Event Logs: Windows Event Viewer shows no crashes (BTHUSB or Audiosrv), indicating a logical bandwidth/protocol denial rather than a service crash.

Resolution / Workaround:

• Rolling back the Intel Bluetooth Driver to v23.140.0.5 completely resolves all issues.

• It appears the newer 24.x driver handles LE bandwidth or multipoint polling too aggressively, choking the audio channel when the Samsung ecosystem sends background continuity pings.

Please investigate the Bluetooth LE bandwidth management in the 24.x driver series regarding high-frequency background polling from multipoint devices.

[Lostinspace]

Hello Chawan_Intel,

Thank you for the detailed troubleshooting steps. I am writing to provide an interim update on my progress.

1. Results of Step 1 (Disable ISST): I completely disabled all ISST-related devices in the Device Manager, while keeping the latest Bluetooth and Wi-Fi drivers (24.30.1.1) installed. To ensure accurate results, I performed multiple tests, including putting the laptop into a deep sleep state for extended periods.

Result: Surprisingly, the issue did NOT occur. The system woke up perfectly every time, with no freezing and sound came out perfectly fine. This may indicates that the conflict lies in how the ISST module interacts with the system's sleep states on the 24.x driver branch. 

But something even strange happened. I enabled the ISST again and the issue did NOT occur too. I did not think this to be happen. And I can assure that this same problem did happened in 24.30.1.1 Bluetooth drivers. Because I can remember when after a windows update I got the 24.30.1.1 driver and problem happened so I had to downgrade to the drivers i had before.

I can't think of any reasonable explanation of what I got from step1. So I am just gonna tell you the exact result, which is above, so you guys can possibly think of what happened. If you need some more information or new tests related to step1 result, please let me know, I am glad to help.

2. Roadblock with Step 2 (Rollback): I attempted to proceed with Step 2. While I could update the Wi-Fi driver, I am unable to install the older Bluetooth driver (version 24.10.0) you provided. The installer is blocked  because a newer version is already installed on my system.

I prefer not to forcibly modify the deep Windows driver repository or use command-line uninstallation tools, as I want to avoid potential registry corruption or system instability. Therefore, I have paused the testing at this stage.

Could you please share this significant Step 1 result with your engineering team? Also, please let me know if this data is sufficient for now, or if you have a safe, official method to bypass the downgrade protection for the Bluetooth driver.

Best regards,

Lostinspace.