Bluetooth Audio Stuttering During WiFi Activity on RTL8852CE

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UPDATE: Kernel Version Correlation Found

After further testing, I’ve identified a clear correlation between kernel versions and the Bluetooth audio stuttering:

  • Kernel 6.11.4-301.fc41.x86_64: :white_check_mark: Works perfectly, no audio stuttering
  • Kernel 6.12.9-200.fc41.x86_64: :x: Audio stutters during WiFi activity

Reproduction Steps:

  1. Fresh Fedora installation (comes with 6.11.4) - Bluetooth audio works perfectly
  2. After sudo dnf update and reboot (updates to 6.12.9) - Bluetooth audio starts stuttering

Key Differences Found Between Kernels (via diff analysis):

  1. WiFi Firmware Changes:

    • 6.11.4: Uses rtw8852c_fw.bin (version 0.27.56.14)
    • 6.12.9: Uses rtw8852c_fw-1.bin (version 0.27.97.0)

  2. Bluetooth Module Changes:

    • Different srcversion identifiers:
      • 6.11.4: B845E3D337E984D458032D7
      • 6.12.9: 8DD395661BE4304F8520852

  3. Additional Firmware Elements in 6.12.9 (not present in 6.11.4):

    • BB version: 00 28 00 00
    • Radio A version: 00 63 00 00
    • NCTL version: 00 11 00 00
    • TXPWR version: 00 69 01 00
    • PWR_TRK version: 00 26 00 00

Both kernels use the same Bluetooth firmware (rtl8852cu_fw_v2.bin), but the module build and handling appear to be different. The additional firmware elements and power tracking in 6.12.9 might be related to the interference issues.

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