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zzZ

Member

Registered: 2015-10-12

Posts: 2

[SOLVED] a2dp-sink connection fails, but only on first connection

I am experiencing a really strange issue with my Bluetooth headphones (Bose QC Ultra). When I boot up my computer and connect to my headphones, the connection will succeed but audio playback will not work. The systemd logs have this error message in them:

$ sudo systemctl status bluetooth
Mar 30 16:20:52 behemoth bluetoothd[784]: Endpoint registered: sender=:1.38 path=/MediaEndpoint/A2DPSource/opus_05
Mar 30 16:20:52 behemoth bluetoothd[784]: Endpoint registered: sender=:1.38 path=/MediaEndpoint/A2DPSink/opus_05_duplex
Mar 30 16:20:52 behemoth bluetoothd[784]: Endpoint registered: sender=:1.38 path=/MediaEndpoint/A2DPSource/opus_05_duplex
Mar 30 16:21:11 behemoth bluetoothd[784]: src/service.c:btd_service_connect() a2dp-sink profile connect failed for BC:87:FA:47:03:C3: Device or resource busy

I can switch to HSP/HFP and get audio, but A2DP will continue to not work. The sync is listed as "available" in pactl, so this section on the wiki does not seem relevant. (just to be safe, I tried these suggested fixes anyways - no luck). What's strange is that this will only occur the first time I try to connect to the headphones after starting my computer. If I disconnect and reconnect, everything works perfectly. So I can work around it, but this is pretty annoying. Anyone have a fix?

Relevant packages:

bluez 5.80-1
linux 6.13.8.arch1-1
wireplumber 0.5.8-1
pipewire 1:1.4.1-1

bluez seems like the most likely culprit to me. I've tried to downgrade to 5.79 and 5.78, but both versions had the same issue. Unfortunately I don't have anything older in my pacman cache. Just to rule out sound server stuff, I've also tried:

• Replacing pipewire with PulseAudio

• Replacing wireplumber with pipewire-media-session

Here is my bluetooth.conf

[General]

# Default adapter name
# Defaults to 'BlueZ X.YZ'
#Name = BlueZ

# Default device class. Only the major and minor device class bits are
# considered. Defaults to '0x000000'.
#Class = 0x000100

# How long to stay in discoverable mode before going back to non-discoverable
# The value is in seconds. Default is 180, i.e. 3 minutes.
# 0 = disable timer, i.e. stay discoverable forever
#DiscoverableTimeout = 0

# Always allow pairing even if there are no agent registered
# Possible values: true, false
# Default: false
#AlwaysPairable = false

# How long to stay in pairable mode before going back to non-discoverable
# The value is in seconds. Default is 0.
# 0 = disable timer, i.e. stay pairable forever
#PairableTimeout = 0

# Use vendor id source (assigner), vendor, product and version information for
# DID profile support. The values are separated by ":" and assigner, VID, PID
# and version.
# Possible vendor id source values: bluetooth, usb (default) or false (disabled)
#DeviceID = bluetooth:1234:5678:abcd

# Do reverse service discovery for previously unknown devices that connect to
# us. For BR/EDR this option is really only needed for qualification since the
# BITE tester doesn't like us doing reverse SDP for some test cases, for LE
# this disables the GATT client functionally so it can be used in system which
# can only operate as peripheral (see also GATT Client option).
# Defaults to 'true'.
#ReverseServiceDiscovery = true

# Enable name resolving after inquiry. Set it to 'false' if you don't need
# remote devices name and want shorter discovery cycle. Defaults to 'true'.
#NameResolving = true

# Enable runtime persistency of debug link keys. Default is false which
# makes debug link keys valid only for the duration of the connection
# that they were created for.
#DebugKeys = false

# Restricts all controllers to the specified transport. Default value
# is "dual", i.e. both BR/EDR and LE enabled (when supported by the HW).
# Possible values: "dual", "bredr", "le"
#ControllerMode = dual

# Maximum number of controllers allowed to be exposed to the system.
# Default=0 (unlimited)
#MaxControllers=0

# Enables Multi Profile Specification support. This allows to specify if
# system supports only Multiple Profiles Single Device (MPSD) configuration
# or both Multiple Profiles Single Device (MPSD) and Multiple Profiles Multiple
# Devices (MPMD) configurations.
# Possible values: "off", "single", "multiple"
#MultiProfile = off

# Permanently enables the Fast Connectable setting for adapters that
# support it. When enabled other devices can connect faster to us,
# however the tradeoff is increased power consumptions. This feature
# will fully work only on kernel version 4.1 and newer. Defaults to
# 'false'.
#FastConnectable = false

# Default privacy setting.
# Enables use of private address.
# Possible values for LE mode: "off", "network/on", "device"
# Possible values for Dual mode: "off", "network/on", "device",
# "limited-network", "limited-device"
#
# - off: Local privacy disabled.
#
# - network/on: A device will only accept advertising packets from peer
# devices that contain private addresses. It may not be compatible with some
# legacy devices since it requires the use of RPA(s) all the time.
#
# - device: A device in device privacy mode is only concerned about the
# privacy of the device and will accept advertising packets from peer devices
# that contain their Identity Address as well as ones that contain a private
# address, even if the peer device has distributed its IRK in the past.

# - limited-network: Apply Limited Discoverable Mode to advertising, which
# follows the same policy as to BR/EDR that publishes the identity address when
# discoverable, and Network Privacy Mode for scanning.
#
# - limited-device: Apply Limited Discoverable Mode to advertising, which
# follows the same policy as to BR/EDR that publishes the identity address when
# discoverable, and Device Privacy Mode for scanning.
#
# Defaults to "off"
#Privacy = off

# Specify the policy to the JUST-WORKS repairing initiated by peer
# Possible values: "never", "confirm", "always"
# Defaults to "never"
#JustWorksRepairing = never

# How long to keep temporary devices around
# The value is in seconds. Default is 30.
# 0 = disable timer, i.e. never keep temporary devices
#TemporaryTimeout = 30

# Enables the device to issue an SDP request to update known services when
# profile is connected. Defaults to true.
#RefreshDiscovery = true

# Default Secure Connections setting.
# Enables the Secure Connections setting for adapters that support it. It
# provides better crypto algorithms for BT links and also enables CTKD (cross
# transport key derivation) during pairing on any link.
# Possible values: "off", "on", "only"
# - "off": Secure Connections are disabled
# - "on": Secure Connections are enabled when peer device supports them
# - "only": we allow only Secure Connections
# Defaults to "on"
#SecureConnections = on

# Enables D-Bus experimental interfaces
# Possible values: true or false
#Experimental = false

# Enables D-Bus testing interfaces
# Possible values: true or false
#Testing = false

# Enables kernel experimental features, alternatively a list of UUIDs
# can be given.
# Possible values: true,false,<UUID List>
# Possible UUIDS:
# d4992530-b9ec-469f-ab01-6c481c47da1c (BlueZ Experimental Debug)
# 671b10b5-42c0-4696-9227-eb28d1b049d6 (BlueZ Experimental Simultaneous Central and Peripheral)
# 15c0a148-c273-11ea-b3de-0242ac130004 (BlueZ Experimental LL privacy)
# 330859bc-7506-492d-9370-9a6f0614037f (BlueZ Experimental Bluetooth Quality Report)
# a6695ace-ee7f-4fb9-881a-5fac66c629af (BlueZ Experimental Offload Codecs)
# 6fbaf188-05e0-496a-9885-d6ddfdb4e03e (BlueZ Experimental ISO socket)
# Defaults to false.
#KernelExperimental = false

# The duration to avoid retrying to resolve a peer's name, if the previous
# try failed.
# The value is in seconds. Default is 300, i.e. 5 minutes.
#RemoteNameRequestRetryDelay = 300

[BR]
# The following values are used to load default adapter parameters for BR/EDR.
# BlueZ loads the values into the kernel before the adapter is powered if the
# kernel supports the MGMT_LOAD_DEFAULT_PARAMETERS command. If a value isn't
# provided, the kernel will be initialized to it's default value.  The actual
# value will vary based on the kernel version and thus aren't provided here.
# The Bluetooth Core Specification should be consulted for the meaning and valid
# domain of each of these values.

# BR/EDR Page scan activity configuration
#PageScanType=
#PageScanInterval=
#PageScanWindow=

# BR/EDR Inquiry scan activity configuration
#InquiryScanType=
#InquiryScanInterval=
#InquiryScanWindow=

# BR/EDR Link supervision timeout
#LinkSupervisionTimeout=

# BR/EDR Page Timeout
#PageTimeout=

# BR/EDR Sniff Intervals
#MinSniffInterval=
#MaxSniffInterval=

[LE]
# Enable/Disable Central Address Resolution.
# 0: disable
# 1: enable
# Defaults to 1
#CentralAddressResolution = 1

# The following values are used to load default adapter parameters for LE.
# BlueZ loads the values into the kernel before the adapter is powered if the
# kernel supports the MGMT_LOAD_DEFAULT_PARAMETERS command. If a value isn't
# provided, the kernel will be initialized to it's default value.  The actual
# value will vary based on the kernel version and thus aren't provided here.
# The Bluetooth Core Specification should be consulted for the meaning and valid
# domain of each of these values.
# LE advertisement interval (used for legacy advertisement interface only)
#MinAdvertisementInterval=
#MaxAdvertisementInterval=
#MultiAdvertisementRotationInterval=

# LE scanning parameters used for passive scanning supporting auto connect
# scenarios
#ScanIntervalAutoConnect=
#ScanWindowAutoConnect=

# LE scanning parameters used for passive scanning supporting wake from suspend
# scenarios
#ScanIntervalSuspend=
#ScanWindowSuspend=

# LE scanning parameters used for active scanning supporting discovery
# proceedure
#ScanIntervalDiscovery=
#ScanWindowDiscovery=

# LE scanning parameters used for passive scanning supporting the advertisement
# monitor Apis
#ScanIntervalAdvMonitor=
#ScanWindowAdvMonitor=

# LE scanning parameters used for connection establishment.
#ScanIntervalConnect=
#ScanWindowConnect=

# LE default connection parameters.  These values are superceeded by any
# specific values provided via the Load Connection Parameters interface
#MinConnectionInterval=
#MaxConnectionInterval=
#ConnectionLatency=
#ConnectionSupervisionTimeout=
#Autoconnecttimeout=

# Scan duration during interleaving scan. Only used when scanning for ADV
# monitors. The units are msec.
# Default: 300
#AdvMonAllowlistScanDuration=
# Default: 500
#AdvMonNoFilterScanDuration=

# Enable/Disable Advertisement Monitor interleave scan for power saving.
# 0: disable
# 1: enable
# Defaults to 1
#EnableAdvMonInterleaveScan=

[GATT]
# GATT attribute cache.
# Possible values:
# always: Always cache attributes even for devices not paired, this is
# recommended as it is best for interoperability, with more consistent
# reconnection times and enables proper tracking of notifications for all
# devices.
# yes: Only cache attributes of paired devices.
# no: Never cache attributes
# Default: always
#Cache = always

# Minimum required Encryption Key Size for accessing secured characteristics.
# Possible values: 0 and 7-16. 0 means don't care.
# Defaults to 0
#KeySize = 0

# Exchange MTU size.
# Possible values: 23-517
# Defaults to 517
#ExchangeMTU = 517

# Number of ATT channels, 1 is mandatory since it is used for ATT fixed channel
# index 2-6 are used for EATT which is optional.
# Possible values: 1-6 (1 disables EATT)
# Default to 1
#Channels = 1

# Export claimed services by plugins
# Possible values: no, read-only, read-write
# Default: read-only
#ExportClaimedServices = read-only

[CSIS]
# SIRK - Set Identification Resolution Key which is common for all the
# sets. They SIRK key is used to identify its sets. This can be any
# 128 bit value or a string value (e.g. product name) which is then hashed.
# Possible Values:
# 16 byte hexadecimal value: 861FAE703ED681F0C50B34155B6434FB
# String value: "My Product Name"
# Defaults to none
#SIRK =

# SIRK Encryption
# Possible values:
# true: Encrypt SIRK when read
# false: Do not encrypt SIRK when read. (plaintext)
# Defaults to true
#Encryption = true

# Total no of sets belongs to this Profile
# Defaults to 0
#Size = 0

# Rank for the device
# Defaults to 0
#Rank = 0

# This enables the GATT client functionally, so it can be disabled in system
# which can only operate as a peripheral.
# Defaults to 'true'.
#Client = true

[AVDTP]
# AVDTP L2CAP Signalling Channel Mode.
# Possible values:
# basic: Use L2CAP Basic Mode
# ertm: Use L2CAP Enhanced Retransmission Mode
#SessionMode = basic

# AVDTP L2CAP Transport Channel Mode.
# Possible values:
# basic: Use L2CAP Basic Mode
# streaming: Use L2CAP Streaming Mode
#StreamMode = basic

[AVRCP]
# Allow SetAbsoluteVolume calls to a peer device that does not advertise the
# AVRCP remote control target profile.  If it does advertise this profile, the
# version is ignored.
#VolumeWithoutTarget = false

# Validate that remote AVRCP profiles advertise the category-2 bit before
# allowing SetAbsoluteVolume calls or registering for EVENT_VOLUME_CHANGED
# notifications.
#VolumeCategory = true

[Policy]
#
# The ReconnectUUIDs defines the set of remote services that should try
# to be reconnected to in case of a link loss (link supervision
# timeout). The policy plugin should contain a sane set of values by
# default, but this list can be overridden here. By setting the list to
# empty the reconnection feature gets disabled.
#ReconnectUUIDs=00001112-0000-1000-8000-00805f9b34fb,0000111f-0000-1000-8000-00805f9b34fb,0000110a-0000-1000-8000-00805f9b34fb,0000110b-0000-1000-8000-00805f9b34fb

# ReconnectAttempts define the number of attempts to reconnect after a link
# lost. Setting the value to 0 disables reconnecting feature.
#ReconnectAttempts=7

# ReconnectIntervals define the set of intervals in seconds to use in between
# attempts.
# If the number of attempts defined in ReconnectAttempts is bigger than the
# set of intervals the last interval is repeated until the last attempt.
#ReconnectIntervals=1,2,4,8,16,32,64

# AutoEnable defines option to enable all controllers when they are found.
# This includes adapters present on start as well as adapters that are plugged
# in later on. Defaults to 'true'.
#AutoEnable=true

# Audio devices that were disconnected due to suspend will be reconnected on
# resume. ResumeDelay determines the delay between when the controller
# resumes from suspend and a connection attempt is made. A longer delay is
# better for better co-existence with Wi-Fi.
# The value is in seconds.
# Default: 2
#ResumeDelay = 2

[AdvMon]
# Default RSSI Sampling Period. This is used when a client registers an
# advertisement monitor and leaves the RSSISamplingPeriod unset.
# Possible values:
# 0x00       Report all advertisements
# N = 0xXX   Report advertisements every N x 100 msec (range: 0x01 to 0xFE)
# 0xFF       Report only one advertisement per device during monitoring period
# Default: 0xFF
#RSSISamplingPeriod=0xFF

Thanks!

Edit: Another interesting data point: I do not have these issues with my AirPods.

Last edited by zzZ (2025-04-04 13:04:29)

nachopro

Member

Registered: 2013-08-23

Posts: 91

Re: [SOLVED] a2dp-sink connection fails, but only on first connection

I'm facing the same issue

PD: I own a Sony WH-1000XM4

bluez 5.80-2
linux 6.13.8.arch1-1
wireplumber 0.5.8-1
pipewire 1:1.4.1-1

Last edited by nachopro (2025-04-01 14:43:57)

nachopro

Member

Registered: 2013-08-23

Posts: 91

Re: [SOLVED] a2dp-sink connection fails, but only on first connection

Hi, I have news! Last Tuesday I installed Sony's Sound Connect on my Android phone and found a firmware update for my headphones. After I updated it, the problem in my setup was solved. Now I can't reproduce the issue, so I'm happy and angry xD because can't help you

Last edited by nachopro (2025-04-03 22:14:27)

zzZ

Member

Registered: 2015-10-12

Posts: 2

Re: [SOLVED] a2dp-sink connection fails, but only on first connection

After updating to bluez 5.82-1, the issue has gone away.