For comparison, I've attached these Android HCI snoop logs, taken when the same headset initiates a connection to an Android handset this time.
>From ~22:00:50 UTC when the ACL was connected between them, one can see that the handset remains chill, allowing the headset to connect any profiles its heart desires. The headset happened to connect only HFP and A2DP signalling here, before going "silent". Then precisely 2s later, the handset accepts the responsibility of connecting the rest -- it connects A2DP media, while the headset then connects AVRCP (probably on some internal timeout). Within 500ms, everything relevant had been connected and configured, and media streaming was underway, showing none of the issues I found with my PC. ** Attachment added: "HeadsetInitiated_Android10.cfa" https://bugs.launchpad.net/ubuntu/+source/pulseaudio/+bug/1941977/+attachment/5522608/+files/HeadsetInitiated_Android10.cfa -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to pulseaudio in Ubuntu. https://bugs.launchpad.net/bugs/1941977 Title: PC streams music over low-quality HFP/SCO connection, instead of A2DP/AVDTP Status in pulseaudio package in Ubuntu: Incomplete Bug description: This issue was first discovered when I got this headset 2 years back: https://www.amazon.co.uk/gp/product/B01C2QCPYI. STEPS * Enable Bluetooth on the PC * Have music or some video playing on the PC * Power on the (already-paired) headset. It automatically connects to the PC. EXPECTED RESULT The PC's audio should now be streamed to the headset, over high-quality A2DP ACTUAL RESULT The PC's audio gets streamed over the low-quality HFP/SCO connection instead. Stopping and resuming the stream changes nothing. I have to manually open Blueman and right-click on the device and select "High-quality A2DP profile", for it to switch to the expected high-quality A2DP transport. HCI snoop logs and verbose bluetoothd-syslogs taken in both headset- initiated and PC-initiated connections are attached. ProblemType: Bug DistroRelease: Ubuntu 20.04 Package: bluez 5.53-0ubuntu3.3 [modified: lib/systemd/system/bluetooth.service] ProcVersionSignature: Ubuntu 5.4.0-74.83-generic 5.4.114 Uname: Linux 5.4.0-74-generic x86_64 ApportVersion: 2.20.11-0ubuntu27.18 Architecture: amd64 CasperMD5CheckResult: skip CurrentDesktop: ubuntu:GNOME Date: Sun Aug 29 03:49:08 2021 InstallationDate: Installed on 2019-06-08 (812 days ago) InstallationMedia: Ubuntu 19.04 "Disco Dingo" - Release amd64 (20190416) InterestingModules: rfcomm bnep btusb bluetooth MachineType: Dell Inc. XPS 13 9380 ProcEnviron: LANGUAGE=en_GB:en PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_GB.UTF-8 SHELL=/bin/bash ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.4.0-74-generic root=UUID=93dae559-0f0d-4e36-9318-ee7154840a9f ro resume=UUID=01c18f00-e0eb-4891-9bf1-3110416d9b39 quiet splash mem_sleep_default=deep vt.handoff=7 SourcePackage: bluez UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 12/14/2020 dmi.bios.vendor: Dell Inc. dmi.bios.version: 1.12.1 dmi.board.name: 0KTW76 dmi.board.vendor: Dell Inc. dmi.board.version: A00 dmi.chassis.type: 10 dmi.chassis.vendor: Dell Inc. dmi.modalias: dmi:bvnDellInc.:bvr1.12.1:bd12/14/2020:svnDellInc.:pnXPS139380:pvr:rvnDellInc.:rn0KTW76:rvrA00:cvnDellInc.:ct10:cvr: dmi.product.family: XPS dmi.product.name: XPS 13 9380 dmi.product.sku: 08AF dmi.sys.vendor: Dell Inc. hciconfig: hci0: Type: Primary Bus: USB BD Address: 9C:B6:D0:99:1D:20 ACL MTU: 1024:8 SCO MTU: 50:8 UP RUNNING PSCAN RX bytes:3313120 acl:776 sco:26275 events:305102 errors:0 TX bytes:255208317 acl:298108 sco:22053 commands:6779 errors:0 mtime.conffile..etc.bluetooth.main.conf: 2020-04-27T23:21:52.866445 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/pulseaudio/+bug/1941977/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp