Bug#805414: gdm3: disable pulseaudio to prevent capturing A2DP sink on session start

[Antoine Beaupré]

On 2017-07-03 15:46:20, Michael Biebl wrote:
> Am 03.07.2017 um 00:05 schrieb Antoine Beaupré:
>> On 2017-07-02 23:43:55, Michael Biebl wrote:
>>> Am 02.07.2017 um 23:36 schrieb Antoine Beaupré:
>>>> On 2017-07-02 23:16:19, Michael Biebl wrote:
>>>
>>>>> Have you tested the workaround from the arch wiki and can you confirm it
>>>>> works?
>>>>
>>>> I cannot, unfortunately, test this anymore, as I have disabled the
>>>> pulseaudio socket as directed earlier, with:
>>>>
>>>> rm /var/lib/gdm3/.config/systemd/user/sockets.target.wants/pulseaudio.socket
>>>>
>>>> I don't know what that was pointing to, so I can't quite restore that
>>>> behavior directly.
>>>
>>> That's from the postinst:
>>>
>>> UNIT=/usr/lib/systemd/user/pulseaudio.socket
>>> USERUNITDIR=/var/lib/gdm3/.config/systemd/user
>>> if ! [ -L $USERUNITDIR/sockets.target.wants/pulseaudio.socket ]; then
>>>   mkdir -p $USERUNITDIR/sockets.target.wants
>>>   ln -sf $UNIT $USERUNITDIR/sockets.target.wants
>>> fi
>>>
>>> You can run that manually or simply re-install the gdm3 package so that
>>> code is run again.
>> 
>> Thanks! I believe I have rolled back the workarounds and implemented the
>> fix default.pa documented in the Arch wiki. Everything seems to work
>> normally now, ie. I can correctly connect through A2DP to my bluetooth
>> speaker.
>
> Since concerns were raised that this might break existing a11y setups, I
> don't plan to make an upload with this change.

I don't understand the impact this could have regarding
accessibility. There are, as far as I know, currently no usable way to
have bluetooth audio working at all in the gdm3 login prompt, because
there's no way to associate a device, so there's no loss of
functionality here. But there *is* a loss of functionality for
everyone (*including* screen reader users) *after* the user is logged
in: they cannot correctly configure bluetooth devices!

Can we get a better idea of the use case you are worried about here?

To be really clear here, the change I am proposing is the one documented
in the Arch wiki and now also in the Debian wiki:

https://wiki.debian.org/BluetoothUser/a2dp#Workaround_2:_disable_pulseaudio.27s_bluetooth_in_gdm

which currently consists of adding the following
/var/lib/gdm3/.config/pulse/default.pa file:

#!/usr/bin/pulseaudio -nF
#

# load system wide configuration
.include /etc/pulse/default.pa

### unload driver modules for Bluetooth hardware
.ifexists module-bluetooth-policy.so
  unload-module module-bluetooth-policy
.endif

.ifexists module-bluetooth-discover.so
  unload-module module-bluetooth-discover
.endif

How would this break accessibility?

Thanks,

A.

-- 
Thoughtcrime does not entail death: thoughtcrime IS death.
                        - Winston Smith, 1984