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slp / krun

krun - run programs from your system in a microVM
MIT License
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Sound not working #5

Closed teohhanhui closed 1 month ago

teohhanhui commented 1 month ago

Sound doesn't seem to be working even when libkrun is built with virtio-snd support, e.g.: https://github.com/teohhanhui/libkrun/tree/virtio-snd (patch adapted from @slp but updated for latest libkrun)

I think we're missing this: https://github.com/teohhanhui/asahi-krun-container/blob/799243343a4546be9e464f9a64d7326d3655e294/entrypoint-user.sh#L7-L9 (again, adapted from @slp's container image)

Should we do this in krun-guest?

teohhanhui commented 1 month ago

This is tricky because the pulseaudio daemon insists on re-executing itself: https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/blob/v17.0/src/daemon/main.c#L592

And we cannot install pulseaudio on the host since the package would conflict.

We can use user namespace with uid remapping for the current user, right? :thinking:

cf. https://github.com/containers/krunvm/commit/da0a1c482484d6abec5c42f8f330a47bd175c4af

slp commented 1 month ago

Yes, we'll need to re-package pulseaudio in a way that doesn't conflict with pipewire, so we can install in on the host and execute it from the VM. I had plans to work on this next week.

teohhanhui commented 1 month ago

Do we basically just set PA_BINARY to /usr/bin/krun-pulseaudio /usr/libexec/krun/pulseaudio and call it a day?

https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/blob/v17.0/src/daemon/main.c#L575

slp commented 1 month ago

We'll probably also need to override the system's alsa & pipewire config (alsa is instructed to redirect output to pipewire) by mounting tmpfs on top of them and writing a custom config for the VM.

teohhanhui commented 1 month ago

Another working alternative is to run it inside of a container. Haha...

At least it's working inside krun, but I haven't got it working inside FEXBash yet... :thinking:

https://gist.github.com/teohhanhui/042a395010d9946ceee14768736e3780

EDIT: Never mind. I don't think this approach works because virtio-snd uses PipeWire backend, and we don't have access to that from within a container?

Weird... Actually, we do have access to /dev/snd/* from within a distrobox container, but not from within the krun VM. Maybe I messed up my rebase of the libkrun patch?

teohhanhui commented 1 month ago

We'll probably also need to override the system's alsa & pipewire config (alsa is instructed to redirect output to pipewire)

I'm not familiar with any of this, but from what I can see:

So I don't think there's anything to do. There's pipewire-alsa which replaces alsa-plugins-pulseaudio. And then there's user config in HOME...

teohhanhui commented 1 month ago

Maybe I messed up my rebase of the libkrun patch?

Okay, getting somewhere with PIPEWIRE_DEBUG=4 krun bash:

[D][02601.369493] pw.thread-loop | [ thread-loop.c: 146 loop_new()] 0xfffc08007e50: new name:Pipewire thread loopfailed to create contextFailed to connect to coresync failedpipewire backend runningStream Audioaudio-outputcould not create new streamcould not connect to the streamInvalid direction prepare could not disconnect stream release pipewire startcould not start stream start pipewire stopcould not stop stream stop State changed: could not update paramsNo buffer recievedassertion failed: bytes_read == to_readdevices::virtio::snd::audio_backendssrc/devices/src/virtio/snd/audio_backends.rsallocating audio backend devices::virtio::snd::devicesrc/devices/src/virtio/snd/device.rsa PCM_INFO request should have a writeable descriptor for the info payload response after the header status responsea PCM_INFO request should have three descriptors total.returned for ctrl msg BAD_MSGOKsnd: process_control()Error processing control message: index= head_index=snd: process_txq_queue()snd: p... (truncated)

Hmm... This seems like just all the messages. Never mind.

teohhanhui commented 1 month ago

https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/issues/3816

Running pactl load-module module-alsa-card device_id=0 manually gets it working.

slp commented 1 month ago

We aren't running udev in the VM. We can simply ship a default.pa that configures the alsa devices on start. It's working here for me, both with native and x86 (w/fex) binaries. It's now just a matter of getting pulseaudio packaged in a decent shape.

teohhanhui commented 1 month ago

We can simply ship a default.pa that configures the alsa devices on start.

We can add a config file in /etc/pulse/default.pa.d, but I don't see a mechanism to only do load-module module-alsa-card device_id=0 when we're running inside krun VM.

Found a solution: pulseaudio -D --load="module-alsa-card device_id=0" --exit-idle-time=-1

m1m1k4tz commented 1 month ago

We aren't running udev in the VM. We can simply ship a default.pa that configures the alsa devices on start. It's working here for me, both with native and x86 (w/fex) binaries. It's now just a matter of getting pulseaudio packaged in a decent shape.

Is this why controllers don’t work?

slp commented 1 month ago

@teohhanhui I've created a pulseaudio-krun package that can be installed side-by-side with pipewire: https://copr.fedorainfracloud.org/coprs/slp/pulseaudio-krun/

Using it with your command line works nicely. We should probably update krun-guest to launch it if present.

slp commented 1 month ago

We aren't running udev in the VM. We can simply ship a default.pa that configures the alsa devices on start. It's working here for me, both with native and x86 (w/fex) binaries. It's now just a matter of getting pulseaudio packaged in a decent shape.

Is this why controllers don’t work?

If by controllers you mean gamepads, no. The problem with gamepads is that there's not Wayland extension to transport that kind of input device, so sommelier can't translate them from the host to the VM.

A possible solution for this is implementing a virtio-input device that would detect and read the events from /dev/input/eventX.

teohhanhui commented 1 month ago

I've created a pulseaudio-krun package that can be installed side-by-side with pipewire: https://copr.fedorainfracloud.org/coprs/slp/pulseaudio-krun/

A few suggestions:

  1. krun-pulseaudio (pulseaudio-krun gives the impression that it's a pulseaudio subpackage / plugin or something...)
  2. I thought about it long and hard, and I think this approach is mistaken. We should rather install pulseaudio in /usr/libexec/krun/pulseaudio, and configure the meson build to only build a few selected targets. This is just perfect for our needs:

I wouldn't mind working on this.

slp commented 1 month ago

2. I thought about it long and hard, and I think this approach is mistaken. We should rather install pulseaudio in /usr/libexec/krun/pulseaudio, and configure the meson build to only build a few selected targets. This is just perfect for our needs:

* https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/blob/v17.0/meson_options.txt#L1-3
* https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/blob/v17.0/src/meson.build#L222-226

I wouldn't mind working on this.

Sounds good to me.

teohhanhui commented 1 month ago

Sound should be working after #9.