Re: Bluetooth connection disconnects every few minutes

W dniu 08.07.2018 o 19:46, Georg Chini pisze:

On 08.07.2018 15:21, Julian Sikorski wrote:

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W dniu 02.07.2018 o 20:09, Julian Sikorski pisze:

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W dniu 02.07.2018 o 18:04, Georg Chini pisze:

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On 02.07.2018 17:58, Julian Sikorski wrote:

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W dniu 29.06.2018 o 21:47, Julian Sikorski pisze:

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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:

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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