Fix some pairing-related issues.

[kareltucek]

This should some of the issues in UltimateHackingKeyboard/firmware#1019

I would appreciate a thorough review of this PR.

Also, this definitely doesn't solve all the problems, but should be a step in the right direction.

[kareltucek]

@mhantsch this should make your uhk usable again. Could you maybe give it a try and let us know what problems you have encountered?

[mondalaci]

The issue is fixed based on my tests. Should I merge this?

CONFIG_BT_MAX_CONN=4 and CONFIG_BT_MAX_PAIRED=20 seem overkill, though. Why so high values?

[kareltucek]

If 20 is an overkill, then why do we have 22 host connection slots?

[kareltucek]

The issue is fixed based on my tests. Should I merge this?

Yes please.

[mondalaci]

CONFIG_BT_MAX_PAIRED is justified, indeed, by the maximum number of paired wireless connections (which is admittedly rather overkill but might be used by some users).

Please explain why CONFIG_BT_MAX_CONN=4 is needed.

[kareltucek]

If we want uhk80 to act as a kvm switch, we need at least two active host connections, plus connection to left half, plus one free connection so that we can keep advertising and do connection-priority magic.

[mhantsch]

If we want uhk80 to act as a kvm switch, we need at least two active host connections, plus connection to left half, plus one free connection so that we can keep advertising and do connection-priority magic.

Can I pair a Bluetooth mouse to the UHK, and it will relay the mouse activities via the active UHK-to-host connection (BT, Dongle, USB left, USB right)? Then the UHK80 would be a true KM switch (no Video, so no V).

(Yeah I know, crazy idea, and yes, technically challenging, and yes, more pressing issues first!)

[mondalaci]

I've already thought of that, but the mentioned feature will come much later.

[kareltucek]

If we want uhk80 to act as a kvm switch, we need at least two active host connections, plus connection to left half, plus one free connection so that we can keep advertising and do connection-priority magic.

Can I pair a Bluetooth mouse to the UHK, and it will relay the mouse activities via the active UHK-to-host connection (BT, Dongle, USB left, USB right)? Then the UHK80 would be a true KM switch (no Video, so no V).

(Yeah I know, crazy idea, and yes, technically challenging, and yes, more pressing issues first!)

Looking forward to a PR ;-).