Latest Raspbian Buster (09/26/19), Thingy:52 automatically disconnects after about 90 seconds

[OmnIoT]

Hi, Just wanted to pass this along... with the latest Raspbian (09/26/19) the thingy52 will consistently disconnect after about 90 seconds (+/- a few seconds). You can easily reproduce by installing any Pi (I've tried a 3 and a zero/w) with the current Raspbian Buster(09/26/19), connecting a thingy via bluetoothctl, and waiting 90 seconds. It doesn't matter if there is activity during those 90 seconds or not (characteristic reads/writes/notifications, etc.). At about 90 seconds you'll get disconnected consistently. On the one hand older Raspbian versions didn't have this issue (that I'm aware of), but on the other I've tested several other BLE sensors with the 09/26/19 build and none of them (so far) have displayed a similar issue. This isn't critical or anything (to me) but thought I would pass it on. Also note that as of today at least (12/17/19) it doesn't make any difference if I've updated the 09/26/19 build with the latest updates or not (apt-get update/upgrade). Lastly, I am running the newest firmware on my Thingy (though my thingy hardware is probably one of the earliest). If I can answer any additional questions let me know but it should be very easy to reproduce. Thanks... 

[OmnIoT]

I went back to Raspbian stretch and confirmed via btmon that with both sensors the OS would previously accept the connection parameter request updates. Not sure what logic controls whether conn parm change requests are accepted, but it appears to have changed in buster unfortunately....

[OmnIoT]

One last update - I think the changes (07/06 + 09/05) here -

git.kernel.org/.../hci_event.c

address this. You can read the comments in the change links, but bottom line is the 07/06 change caused the OS to start rejecting Parameter Update Requests and the 09/05 change subsequently backed that change out (due to devices no longer being able to connect no doubt). I'm guessing the first change made it into the current buster release and the second one will hopefully be in the next release. I couldn't find for sure that that's the case so if anyone reading this knows how to verify that's correct that would be great. Pretty well explains the behavior though...

PS - feel free to close this if it needs to be closed. Thx