[pulseaudio-discuss] Bluetooth connection disconnects every few minutes

Julian Sikorski belegdol at gmail.com
Wed Aug 1 17:46:26 UTC 2018


W dniu 09.07.2018 o 18:51, Julian Sikorski pisze:
> W dniu 08.07.2018 o 19:46, Georg Chini pisze:
>> On 08.07.2018 15:21, Julian Sikorski wrote:
>>> W dniu 02.07.2018 o 20:09, Julian Sikorski pisze:
>>>> W dniu 02.07.2018 o 18:04, Georg Chini pisze:
>>>>> On 02.07.2018 17:58, Julian Sikorski wrote:
>>>>>> W dniu 29.06.2018 o 21:47, Julian Sikorski pisze:
>>>>>>> Hi list,
>>>>>>>
>>>>>>> I have noticed that the bluetooth connection between my laptop (Intel
>>>>>>> 7260) and my headphones (Sennheiser Momentum Wirelless) is very
>>>>>>> unreliable. While under Windows 10 devices stay connected for
>>>>>>> hours on
>>>>>>> end, under Fedora 28 the connection is lost every few minutes at
>>>>>>> most.
>>>>>>> Often the connection will be reestablished only to be lost again.
>>>>>>> bluetoothd shows messages like:
>>>>>>>
>>
>>>>>>> I am not sure where to look further. Does it look like an issue with
>>>>>>> pulseaudio, or a deeper problem with linux bluetooth stack? Thanks
>>>>>>> for
>>>>>>> your input in advance!
>>>>>>>
>>>>>>> Best regards,
>>>>>>> Julian
>>>>>> This is what is logged by pulseaudio at the time the connection is
>>>>>> lost:
>>>>>>
>>>>>> ( 118.064|  34.694) I: [bluetooth] module-bluez5-device.c: FD error:
>>>>>> POLLERR POLLHUP
>>>>>> ( 118.064|   0.000) I: [bluetooth] bluez5-util.c: Transport
>>>>>> /org/bluez/hci0/dev_00_1B_66_81_8D_76/fd27 auto-released by BlueZ or
>>>>>> already released
>>>>>> ( 118.064|   0.000) I: [pulseaudio] backend-native.c: Lost RFCOMM
>>>>>> connection.
>>>>>>
>>>>>>
>>>>>  From what you are writing, it looks to me as if the issue is in the
>>>>> USB
>>>>> stack and the BT dongle keeps disconnecting/connecting. Have you
>>>>> tried another dongle?
>>>> Hi,
>>>>
>>>> I unfortunately do not own any other dongles. I tried getting some
>>>> useful info with btmon but the log seems flooded with way too many
>>>> messages to make anything out.
>>>>
>>> Hi Georg,
>>>
>>> it looks like the problem is more related to how the dongle interacts
>>> with this specific headphone model. I have recently bought another one
>>> for running (AfterShokz Trekz Air) and it works perfectly, connecting
>>> automatically, staying connected and even switching profiles
>>> automatically without issues so far.
>>> The hci0: last event is not cmd complete (0x0f) message seems harmless
>>> as it spams the dmesg output regardless of the device connected (and
>>> also when no device is connected at all.
>>> It appears that whatever is happening it makes the dongle reconnect:
>>>
>>> [nie lip  8 15:14:12 2018] usb 2-1.4: USB disconnect, device number 6
>>> [nie lip  8 15:14:12 2018] usb 2-1.4: new full-speed USB device number 7
>>> using ehci-pci
>>> [nie lip  8 15:14:12 2018] usb 2-1.4: New USB device found,
>>> idVendor=8087, idProduct=07dc, bcdDevice= 0.01
>>> [nie lip  8 15:14:12 2018] usb 2-1.4: New USB device strings: Mfr=0,
>>> Product=0, SerialNumber=0
>>> [nie lip  8 15:14:12 2018] Bluetooth: hci0: read Intel version:
>>> 3707100180012d0d2a
>>> [nie lip  8 15:14:12 2018] Bluetooth: hci0: Intel device is already
>>> patched. patch num: 2a
>>>
>>> Where would you recommend to look for reasons for this behaviour? btmon?
>>> Thank you for the pointers!
>>>
>>> Best regards,
>>> Julian
>>>
>>>
>> Hi Julian,
>>
>> sorry, I have no further ideas. Maybe Luiz can help you to investigate.
>> To me it looks like the headphone is sending something that makes the
>> dongle reset.
>>
>> Regards
>>             Georg
> 
> Hi Georg,
> 
> no worries - hopefully Luiz will find some time to look into this.
> In the meantime I have been getting acquainted with btmon. I have
> managed to pinpoint the exact moment during which sound stops coming
> through the headphones and starts coming through the laptop speakers. In
> the below testcase, it happens at 18:42:58:
> 
> < ACL Data TX: Handle 256 flags 0x02 dlen 850
>                               #1825 [hci0] 18:42:58.908586
>       Channel: 450 len 846 [PSM 25 mode 0] {chan 2}
> < ACL Data TX: Handle 256 flags 0x02 dlen 850
>                               #1826 [hci0] 18:42:58.928877
>       Channel: 450 len 846 [PSM 25 mode 0] {chan 2}
> @ MGMT Event: Class Of Device Changed (0x0007) plen 3
>                            {0x0002} [hci0] 18:43:00.653578
>         Class: 0x000000
>           Major class: Miscellaneous
>           Minor class: 0x00
> @ MGMT Event: Class Of Device Changed (0x0007) plen 3
>                            {0x0001} [hci0] 18:43:00.653578
>         Class: 0x000000
>           Major class: Miscellaneous
>           Minor class: 0x00
> @ MGMT Event: New Settings (0x0006) plen 4
>                            {0x0002} [hci0] 18:43:00.653609
>         Current settings: 0x00000ada
>           Connectable
>           Discoverable
>           Bondable
>           Secure Simple Pairing
>           BR/EDR
>           Low Energy
>           Secure Connections
> @ MGMT Event: New Settings (0x0006) plen 4
>                            {0x0001} [hci0] 18:43:00.653609
>         Current settings: 0x00000ada
>           Connectable
>           Discoverable
>           Bondable
>           Secure Simple Pairing
>           BR/EDR
>           Low Energy
>           Secure Connections
> = bluetoothd: Unable to get io data for Headset Voice gateway:
> getpeername: Transport endpoint is not connected..   18:43:00.654133
> = Close Index: 7C:5C:F8:B2:DF:08
>                                     [hci0] 18:43:00.678348
> @ MGMT Event: Index Removed (0x0005) plen 0
>                            {0x0002} [hci0] 18:43:00.678372
> @ MGMT Event: Index Removed (0x0005) plen 0
>                            {0x0001} [hci0] 18:43:00.678372
> = Delete Index: 7C:5C:F8:B2:DF:08
>                                     [hci0] 18:43:00.678377
> = bluetoothd: Endpoint unregistered: sender=:1.1492
> path=/MediaEndpoint/A2DPSource
> 18:43:00.678966
> = bluetoothd: Endpoint unregistered: sender=:1.1492
> path=/MediaEndpoint/A2DPSink
> 18:43:00.678984
> 
> I am copying linux-bluetooth, maybe someone there will have an idea as
> well. Thank you for all your help in advance!
> 
> Best regards,
> Julian

Hi all,

I tried to get more information using hcidump, but it does not appear
very interesting. I am attaching it here just in case. The last entry
appearing - command complete (read encryption key size) - appears upon
successful connection, not when the connection is dropped. How else
could I try to figure out what is being sent at the time of
disconnection? Thank you!

Best regards,
Julian
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