Re: [PATCH] hfp_hf_bluez5: Fix re-registering a modem for a device

[Marcel Holtmann <marcel@holtmann.org>]

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Hi Johan,

>>> Even for outgoing pairing requests we may receive the UUIDs property
>>> changed after the device is paired and try to register it twice.
>>> 
>>> The easiest way to reproduce this is when Extended Inquiry Response is
>>> supported.
>>> 
>>> When the device is paired, we receive the "Paired" PropertyChanged,
>>> inside modem_register_from_proxy(), g_dbus_proxy_get_property() gets
>>> the UUIDs extracted from the EIR data.  Later, when the service
>>> discovery is finished, the UUIDs property is re-sent and both may
>>> contain the HFP AG UUID.
>> 
>> My sources indicated to me that BlueZ should perform the SDP query
>> first, and then signal Paired.  Is this something we can not count
>> on or is this an implementation issue inside BlueZ itself?
> 
> BlueZ has always done pairing first and only then SDP. This is because
> there are security mode 3 devices out there that do not permit any kind
> of connection before pairing has been completed (i.e. even if we wanted
> to do SDP first we can't with them). That said, we do at least delay the
> NewConnection() callback until SDP has been completed.

so when are we sending "Paired" property? We might have to delay that property update until SDP finished.

We have to make sure that we finished SDP after the pairing before updating any clients with property changes.

Regards

Marcel