Hi Tomas, On Wed, 09 Sep 2020, 17:29:44 +0200, Tomas Kuchta wrote:

I expected confusion, ....

To clarify - I am not asking about forwarding sound through remote connection to ssh/vnc client side.

I would like to figure out how to access sound devices on vnc server to play sounds on vnc server.

As described in the original post - it seems that something is restricting access to local HW devices on the server. Perhaps it is not access control/ restriction, but some conflict or exclusive access from something on the server side. I am not sure.

first thing which comes to mind is group "audio"; IIRC only members of the "audio" group are allowed to access sound related devices. When you're using PulseAudio, there might be an issue if it allows access for other/remote services at all. You can use "paprefs" to allow/disallow access to those devices which PA already controls on your local system.

Thank you, Tomas

HTH, cheers. l8er manfred

On Thu, 2020-09-10 at 16:19 +0930, Simon Lees wrote:

On 9/10/20 1:29 AM, Manfred Hollstein wrote:

...

Hi Tomas,

On Wed, 09 Sep 2020, 17:29:44 +0200, Tomas Kuchta wrote:

...

I expected confusion, ....

To clarify - I am not asking about forwarding sound through remote connection to ssh/vnc client side.

I would like to figure out how to access sound devices on vnc server to play sounds on vnc server.

As described in the original post - it seems that something is restricting access to local HW devices on the server. Perhaps it is not access control/ restriction, but some conflict or exclusive access from something on the server side. I am not sure.

first thing which comes to mind is group "audio"; IIRC only members of the "audio" group are allowed to access sound related devices. When you're using PulseAudio, there might be an issue if it allows access for other/remote services at all. You can use "paprefs" to allow/disallow access to those devices which PA already controls on your local system.

This is no longer true, now it is managed by logind, I can "ssh -X" into my desktop from my laptop launch clementine and play music through my desktop speakers, however that might also be related to me also being currently logged into that machine although they were treated as separate sessions. How to configure logind / polkit to allow non graphical users to have audio, i've only really messed with it for network.

https://www.freedesktop.org/software/systemd/man/loginctl.html#

Thank you all for the suggestions - it is resolved by adding myself to audio group. A few observations: polkit - I could not figure out the polkit in any reasonable time - even what it actually controls, how, it works, how and what to configure, even the format of its default config is not clearly/easily described. I am not even sure if it actually is active - given your suggestions - I trust that it is. paprefs - the network settings had no effect on the local sound device "invisibility". groups - adding self to audio group + logout/restart vnc/login made all the local audio devices visible to me in vncserver and the sound works. It is complete mystery to me - how I could have had access to the sound devices without being audio group member from local graphical session. Only root and audio group has access to the sound devices /dev/snd/* So, I should not have been able to make any sounds without the audio group membership: ls -l /dev/snd/* crw-rw----+ 1 root audio 116, 17 Sep 10 19:18 /dev/snd/controlC0 crw-rw----+ 1 root audio 116, 4 Sep 10 19:18 /dev/snd/controlC1 crw-rw----+ 1 root audio 116, 7 Sep 10 19:18 /dev/snd/controlC2 crw-rw----+ 1 root audio 116, 15 Sep 10 19:18 /dev/snd/hwC0D0 crw-rw----+ 1 root audio 116, 16 Sep 10 19:18 /dev/snd/hwC0D2 crw-rw----+ 1 root audio 116, 9 Sep 10 19:51 /dev/snd/pcmC0D0c crw-rw----+ 1 root audio 116, 8 Sep 10 19:51 /dev/snd/pcmC0D0p crw-rw----+ 1 root audio 116, 14 Sep 10 19:50 /dev/snd/pcmC0D10p crw-rw----+ 1 root audio 116, 10 Sep 10 19:50 /dev/snd/pcmC0D3p crw-rw----+ 1 root audio 116, 11 Sep 10 19:50 /dev/snd/pcmC0D7p crw-rw----+ 1 root audio 116, 12 Sep 10 19:50 /dev/snd/pcmC0D8p crw-rw----+ 1 root audio 116, 13 Sep 10 19:50 /dev/snd/pcmC0D9p crw-rw----+ 1 root audio 116, 3 Sep 10 19:51 /dev/snd/pcmC1D0c crw-rw----+ 1 root audio 116, 2 Sep 10 19:51 /dev/snd/pcmC1D0p crw-rw----+ 1 root audio 116, 6 Sep 10 19:51 /dev/snd/pcmC2D0c crw-rw----+ 1 root audio 116, 5 Sep 10 19:51 /dev/snd/pcmC2D0p crw-rw----+ 1 root audio 116, 1 Sep 10 19:18 /dev/snd/seq crw-rw----+ 1 root audio 116, 33 Sep 10 19:18 /dev/snd/timer If someone could explain this in a few sentences - I would really appreciate it. Thanks again, Tomas -- To unsubscribe, e-mail: opensuse-support+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-support+owner@opensuse.org

On Fri, 2020-09-11 at 12:52 +0930, Simon Lees wrote:

On 9/11/20 10:05 AM, tomas.kuchta.lists@gmail.com wrote:

...

If someone could explain this in a few sentences - I would really appreciate it.

https://wiki.ubuntu.com/Audio/TheAudioGroup except instead of using consolekit it now uses parts of the systemd/logind stack. In short a user who is logged in graphically will gain access to audio / keyboard / mouse / display devices. A user logged in remotely should generally not have access as a security feature.

Thank you Simon - I am starting to connect the dots - this is real deep rabbit hole though. Carlos mentioned seats - I thought that it is just bad translation for user account - I am slowly starting to remember the old mainframes and Vax's and their system topology. I will dig little deeper - though - I am not sure that this whole thing is meant to be dynamically configurable by user rather than rewriting sddm or systemd or .... to implement assigning seat to vnc session when there is no active local session with the seat need + some sort of seat switching or moving HW around the seats with priorities ..... There seems to be handful of random people trying to figure this out every decade. There is a lot of info about introspection API - not so much how to control it beside header files and programming interface description to D.Bus. Maybe, creating a seat for VNC session and assigning a sound card to it is as simple as adding some magic d.Bus calls to VNC xstartup. My early guess is that I will not be able to come up with anything better than the audio group membership with all its possible side effects - within a day or two before I giving up. Have a great weekend, Tomas -- To unsubscribe, e-mail: opensuse-support+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-support+owner@opensuse.org

11.09.2020 13:31, Carlos E. R. пишет:

...

Carlos mentioned seats - I thought that it is just bad translation for user account - I am slowly starting to remember the old mainframes and Vax's and their system topology.

No, it refers to the user that is seated at the machine. It is assumed that the user that has the currently active local session has the seat.

No, "seat" refers to collection hardware that is considered to belong to the same "workplace". I.e. monitor, keyboard, mouse.

On 11/09/2020 23.27, Dave Howorth wrote:

On Fri, 11 Sep 2020 22:30:19 +0300 Andrei Borzenkov wrote:

...

11.09.2020 13:31, Carlos E. R. пишет:

...

...

Carlos mentioned seats - I thought that it is just bad translation for user account - I am slowly starting to remember the old mainframes and Vax's and their system topology.

No, it refers to the user that is seated at the machine. It is assumed that the user that has the currently active local session has the seat.

No, "seat" refers to collection hardware that is considered to belong to the same "workplace". I.e. monitor, keyboard, mouse.

Exactly, although in this context it might be important to mention the sound hardware too...

Well, no: the person that has the seat is given the sound as well :-) And the DVD, the sticks, video... -- Cheers / Saludos, Carlos E. R. (from 15.1 x86_64 at Telcontar)

On 9/11/20 5:16 PM, tomas.kuchta.lists@gmail.com wrote:

On Fri, 2020-09-11 at 12:52 +0930, Simon Lees wrote:

...

On 9/11/20 10:05 AM, tomas.kuchta.lists@gmail.com wrote:

...

If someone could explain this in a few sentences - I would really appreciate it.

https://wiki.ubuntu.com/Audio/TheAudioGroup except instead of using consolekit it now uses parts of the systemd/logind stack. In short a user who is logged in graphically will gain access to audio / keyboard / mouse / display devices. A user logged in remotely should generally not have access as a security feature.

Thank you Simon - I am starting to connect the dots - this is real deep rabbit hole though.

Carlos mentioned seats - I thought that it is just bad translation for user account - I am slowly starting to remember the old mainframes and Vax's and their system topology.

I will dig little deeper - though - I am not sure that this whole thing is meant to be dynamically configurable by user rather than rewriting sddm or systemd or .... to implement assigning seat to vnc session when there is no active local session with the seat need + some sort of seat switching or moving HW around the seats with priorities .....

There seems to be handful of random people trying to figure this out every decade. There is a lot of info about introspection API - not so much how to control it beside header files and programming interface description to D.Bus. Maybe, creating a seat for VNC session and assigning a sound card to it is as simple as adding some magic d.Bus calls to VNC xstartup.

My early guess is that I will not be able to come up with anything better than the audio group membership with all its possible side effects - within a day or two before I giving up.

If its a signal user machine or you trust all the users that you want to give access to the audio group then there are no downsides to adding the user to the audio group. The defaults these days is users shouldn't have to because they will login normally. The reason it is setup like this is for places like universities where multiple users may share the same computer in a lab but you only want the one that is actually sitting at the desk in front of the PC to have access (This is the idea of the user with the seat). Atleast when I was at uni it was possible to ssh into a imac that someone else was sitting at and play music on there computer, they couldn't do anything to stop the music this is not ideal so the default configuration prevents it, in your case you want it for good reason hence needing to do something non standard. -- Simon Lees (Simotek) http://simotek.net Emergency Update Team keybase.io/simotek SUSE Linux Adelaide Australia, UTC+10:30 GPG Fingerprint: 5B87 DB9D 88DC F606 E489 CEC5 0922 C246 02F0 014B

On 11/09/2020 02.35, tomas.kuchta.lists@gmail.com wrote:

On Thu, 2020-09-10 at 16:19 +0930, Simon Lees wrote:

Only root and audio group has access to the sound devices /dev/snd/* So, I should not have been able to make any sounds without the audio group membership:

ls -l /dev/snd/* crw-rw----+ 1 root audio 116, 17 Sep 10 19:18 /dev/snd/controlC0

............^ Notice that '+'. There are ACLs. Access Control Lists.

If someone could explain this in a few sentences - I would really appreciate it.

-- Cheers / Saludos, Carlos E. R. (from 15.1 x86_64 at Telcontar)