Some phones can have trouble when using the strict AT syntax parser for
HFP. So far, this has only been evidenced with the Samsung Wave, which
works fine with the permissive syntax parser.
Several other phones have been tested with the permissive parser and
seem to work OK.
If BlueZ exits during an outstanding Connect/Disconnect operation,
oFono can crash due to the pending call finishing on an already-removed
modem object.
If an adapter or device is removed any data associate should be removed,
otherwise the next time they appear/are created the drivers may not
asssociate again.