Matthias Reichl wrote: > Userspace expects to see a HDMI pcm, so remove the somewhat broken > front and iec958 pcms and add a proper hdmi pcm instead. > > The hdmi pcm supports HD/HBR audio passthrough and relays the IEC958 > status bits on to the kernel driver so it can switch to HBR audio > packets if needed. The control hook is marked optional because kernels > before 5.14 didn't expose the IEC958 controls. > > The default pcm never worked as dmix doesn't support the iec958 format. > So drop dmix, only use plug and softvol, and use the hdmi pcm for > iec958 formatting. I can confirm the upstream cards/vc4-hdmi.conf is not usable, and RPiOS ships a patched version (which was an earlier version of this patch). I've tested this version with RPiOS bullseye and all seems good. I could play stereo and multi-channel PCM from VLC. I could also play DTS, DTS-HD and TrueHD formats as passthrough using kodi. It would be good if we can switch from a custom version of vc4-hdmi.conf to an upstream version in RPiOS when this is merged. Tested-by: Dom Cobley <popcornmix@xxxxxxxxx>
