Arch Linux

Description:
The autoconnection of older bluetooth devices don't work.

Scince kernel 5.1.1 some of my my bluetooth devices are unable to auto-reconnect. I can connect them without problems, but
once I turn them off and on again an unending sequence of connections and disconnections begins.
On our forums there is more talk about bluetooth devices unable to connect.

The reason seemed to be a upstream-commit:
Link for commit which causes the issue: https://github.com/torvalds/linux/commit/d5bb334a8e171b262e48f378bd2096c0ea458265

Fedora already applied an patch in the kernel 5.1.4 release (see link below).

[PATCH] Bluetooth: Check key sizes only when Secure Simple Pairing is enabled

The encryption is only mandatory to be enforced when both sides are using
Secure Simple Pairing and this means the key size check makes only sense
in that case.

On legacy Bluetooth 2.0 and earlier devices like mice the encryption was
optional and thus causing an issue if the key size check is not bound to
using Secure Simple Pairing.

See:
https://src.fedoraproject.org/rpms/kernel/c/10868cd2f96f545744848175bad5bf88dda139a8?branch=f30

Additional info:
* Kernel 5.1.x

* config and/or log files etc.:
---- manual connection ok ---------
[bluetooth]# connect E0:D1:E6:07:62:E1
Attempting to connect to E0:D1:E6:07:62:E1
[CHG] Device E0:D1:E6:07:62:E1 Connected: yes
Connection successful
[CHG] Device E0:D1:E6:07:62:E1 ServicesResolved: yes
---- turned off speakers and on again ----
[CHG] Device E0:D1:E6:07:62:E1 ServicesResolved: no
[CHG] Device E0:D1:E6:07:62:E1 Connected: no
[CHG] Device E0:D1:E6:07:62:E1 Connected: yes
[CHG] Device E0:D1:E6:07:62:E1 Connected: no
[CHG] Device E0:D1:E6:07:62:E1 Connected: yes
[CHG] Device E0:D1:E6:07:62:E1 Connected: no
[CHG] Device E0:D1:E6:07:62:E1 Connected: yes
[CHG] Device E0:D1:E6:07:62:E1 Connected: no
[CHG] Device E0:D1:E6:07:62:E1 Connected: yes
[CHG] Device E0:D1:E6:07:62:E1 Connected: no

* link to upstream bug report:
https://src.fedoraproject.org/rpms/kernel/c/10868cd2f96f545744848175bad5bf88dda139a8?branch=f30

Steps to reproduce:
Add Bluetooth 2.0 and earlier devices, connect and reboot. The Device don't autoconnect again.