Public bug reported: Ubuntu 26.04's official BlueZ package (5.85-4ubuntu0.3) contains an A2DP remote endpoint cache regression that causes Bluetooth audio negotiation failures.
Hardware: - Lenovo ThinkPad T14s - Intel Bluetooth adapter - beyerdynamic AVENTHO 200 headphones - Samsung Galaxy S24 Expected behavior: The headphones should maintain simultaneous Bluetooth Multipoint connections to Ubuntu and the Samsung S24, with Ubuntu using high-quality A2DP audio. Actual behavior: When both devices are connected, Ubuntu frequently loses A2DP and falls back to HFP/HSP or the "off" audio profile. The problem also occurs during automatic Bluetooth reconnection. Relevant BlueZ errors: profiles/audio/a2dp.c:load_remote_sep() Unable to load LastUsed: rseid 7 not found profiles/audio/avdtp.c:cancel_request() Abort: Connection timed out (110) WirePlumber additionally reports: - Failed codec switching (org.bluez.Error.Failed) - Invalid A2DP endpoint (/sep7) - Failed to switch codec (-19) Root cause: The Ubuntu BlueZ 5.85-4ubuntu0.3 source contains a regression in profiles/audio/a2dp.c, where the loop responsible for loading cached A2DP codec capabilities contains an incorrect condition: for (i = 0, size = strlen(caps); i < size && i >= 2; i += 2) Since i starts at zero, the loop never executes. This regression has already been fixed upstream: https://kernel.googlesource.com/pub/scm/bluetooth/bluez/+/b7d71e5067856b0daf2f1f73b3fc95483236610e Verified workaround: I downloaded Ubuntu's official BlueZ 5.85-4ubuntu0.3 source package, applied upstream commit b7d71e5, and rebuilt it as 5.85-4ubuntu0.3+local1. After installing the patched package, Bluetooth Multipoint works correctly with both devices simultaneously connected. The original A2DP negotiation problem is resolved. Requested fix: Please backport upstream commit b7d71e5 into the Ubuntu 26.04 BlueZ package through a stable release update (SRU). Note: I am currently running the locally patched package because the official Ubuntu version was affected. This also prevents Apport from accepting an automatic bug report. ** Affects: bluez (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2170509 Title: BlueZ 5.85 A2DP cache regression causes Bluetooth Multipoint failures on Ubuntu 26.04 (fixed upstream) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/bluez/+bug/2170509/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
