838080 - [b2g-bluetooth] Cannot receive all events after a series of actions

Status: RESOLVED FIXED

(Core :: DOM: Device Interfaces, defect)

Description

[Gina Yeh [:gyeh] [:ginayeh]]

* Environment:
Phone - Unagi
gaia master(git): 50f724828e40e63d5634fec40b9ecde1c74b461b
gecko b2g-18(hg): 2ae874433a14

* STR:
1. Launch Settings and turn off Bluetooth
2. Press Home button and launch Gallery
3. Select one picture and share by Bluetooth Transfer
4. Tap cancel when you see a list of paired devices
5. Go back to Settings

* Expected Result:
- Nearby devices are shown
- Should be able to unpair with a paired device

* Actual Result:
- No nearby devices are shown
- After unpairing, the device is still shown in the list of paired devices

Comment 1

[Gina Yeh [:gyeh] [:ginayeh]]

I checked the implementation in Gecko. The root cause is that the Bluetooth Transfer app is killed after tapping "Cancel" button, which triggers function UnregisterAllSignalHandlers() and all signal handlers are removed. That's why we cannot receive events like ondevicefound/ondevicecreate/onadapteradded in Settings app. 

An proper way for this situation is that we should only remove signal handlers regarding to the just-killed app rather than all signal handlers.

Comment 2

[Gina Yeh [:gyeh] [:ginayeh]]

Attachment: Patch 1(v1): Don't remove all observers in signal table when child process is killed

When a child process is killed, only signal handlers for child process are removed from table in BluetoothService.

Comment 3

[Gina Yeh [:gyeh] [:ginayeh]]

Nominate as tef+

Without this patch, the Bluetooth part in Settings app cannot work for scenario in Comment 0.

Comment 4

[Gina Yeh [:gyeh] [:ginayeh]]

Attachment: Final patch: Don't remove all observers in signal table when child process is killed, r=echou

Comment 5

[Mozilla RelEng Bot]

Try run for c6257978d3cb is complete.
Detailed breakdown of the results available here:
    https://tbpl.mozilla.org/?tree=Try&rev=c6257978d3cb
Results (out of 14 total builds):
    success: 14
Builds (or logs if builds failed) available at:
http://ftp.mozilla.org/pub/mozilla.org/firefox/try-builds/[e-mail]-c6257978d3cb

Comment 6

[Mozilla RelEng Bot]

Try run for cf7e0db3ead0 is complete.
Detailed breakdown of the results available here:
    https://tbpl.mozilla.org/?tree=Try&rev=cf7e0db3ead0
Results (out of 18 total builds):
    success: 17
    warnings: 1
Builds (or logs if builds failed) available at:
http://ftp.mozilla.org/pub/mozilla.org/firefox/try-builds/[e-mail]-cf7e0db3ead0

Comment 7

[Gina Yeh [:gyeh] [:ginayeh]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/3a7b2f3a36a6

Comment 8

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/3a7b2f3a36a6

Comment 9

[Lukas Blakk [:lsblakk] use ?needinfo]

Not blocking but tracking, please nominate for uplift with a clearer description of the risk/reward.

Comment 10

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/releases/mozilla-b2g18/rev/ca810a60c85a