[Bug 1731467] Re: Cannot pair BLE remote devices when using combo BT SoC

[Konrad Zapałowicz]

** Description changed:

  It has been observed that sometimes it is not possible to pair with
  BLE remote devices when the host system is using combo (WiFi + BT)
  chip.
  
  The root cause of the disconnection has been identified as coming from
  the internal to bluez timeout. If bluez does not hear any reply from for
  two seconds the link is automagically disconnected. The reason fro the
  silence is not however a failure of the remote device but quite often a
  delay in the WiFi/BT combo driver that causes the packages not to reach
  the bluez stack.
  
+ [Impact]
+ 
+ Not possible to pair BLE remote devices such as sensors and such with
+ Ubuntu when the host system uses BT+WiFi combo SoC. The connection
+ attempt is disturbed with a timeout.
+ 
+ [Fix]
+ 
+ It has been fixed by increasing the timeout value from 2 seconds to
+ 4 seconds. It is enough for the events to reach the stack (measured
+ that it takes between 3 and 3.5 seconds).
+ 
+ [Testcase]
+ 
+ Tested with the device that failed to connect to Ubuntu Core gateway.
+ It fails w/o the patch, it connects just fine with the patch applied.
+ 
+ [Regression Potential]
+ 
+ Very small. The increased timeout is taken into consideration only for
+ new and scan report triggered connections. It will not make any already
+ working device to fail to pair.
+ 
+ [Other Info]
+ 
  The bug has been discussed and fixed here:
  
  https://marc.info/?l=linux-bluetooth&m=150824844606937&w=2
  
  [Patch]
  
  https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-
  next.git/commit/?id=1f01d8be0e6a04bd682a55f6d50c14c1679e7571
  
- [Impact]
- 
- Fixing this bug will enable xenial based Ubuntu core devices such as
- gateways connect to various BLE sensors.
- 
- [Regression Potential]
- 
- Although the timeout has been increased the value is still very low
- (4 seconds) therefore should not have a negative impact. It is
- taken into consideration only during pairing and for connections that
- are triggered by the scan report.
- 
- [Other Info]
-  
  The patch has been accepted by the upstream and will be a part of the next
  kernel release. Currently in the bluetooth-next tree.

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https://bugs.launchpad.net/bugs/1731467

Title:
  Cannot pair BLE remote devices when using combo BT SoC

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