On Tue, 3 Feb 2026 at 15:32, Gerd Hoffmann <[email protected]> wrote:
> > I have done more research into the virtio specifications and edk2
> > source and determined the most viable solution would be to expand the
> > OvmfPkg with a VirtioSoundDxe driver. Edk2 supports a generic
> > EFI_VIRTIO_DEVICE_PROTOCOL and a helper library for virtio devices.
> > Leveraging these features from edk2 would make communication with the
> > sound device trivial.
>
> Well, not trivial I'd say, but most likely easier than any other option.
>
> > The biggest question I have on my mind is the stability/jitter issues
> > with sending/receiving audio data. The simplest solution I have is
> > producing an event with a notify function to be triggered when the
> > device finishes processing an audio buffer. That way the consumer can
> > register a routine to place more audio data into the stream queue
> > asynchronously without jittering audio.
>
> edk2 runs all hardware in polling mode, and you'll go register a timer
> to regularly check your device, which effectively is cooperative
> multitasking. I expect you'll see latency spikes if something is busy
> and doesn't give up the CPU.
>
> What is the intended use case?
Apart from gimmicks, ultimately, accessibility
> I suspect that'll be just playing sine
> wave beeps or short (a few seconds at most) sound samples to get the
> attention of the user sitting in front of the screen. For that it'll
> probably work best to just pass the complete sample buffer down to the
> (virtual) sound hardware.
Which should be doable for the real use-case.
We may also want input for voice control, but hopefully that would also
be short samples.
> For contiguous playback you'll need at least two buffers, one used by
> the hardware for playback and one for the player application to refill.
Happy to kick that can down the road for someone who cares :)
> And, yes, some kind of notification that the hardware finished
> processing the buffer makes sense, so the caller can either refill the
> buffer or release the memory. Could be as simple as passing both sample
> buffer and notification function pointer to the sound driver when
> queuing up a buffer for playback.
>
> HTH & take care,
Thanks!
/
Leif
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