When using the stable version of the Linux 6.1 kernel, many users have found that the HDMI audio output of their AMD devices does not work properly. This is a rather serious bug and the upstream developers are working on fixing it.

After some investigation, the problem was pinned down to a recent refactoring of the ALSA HDA/HDMI driver code that broke existing AMD hardware support with the “use only dynamic PCM device allocation” function code. Fortunately this feature change was only merged during the Linux 6.1 merge window, so only Linux 6.1 and earlier Linux 6.2 development states were affected by this AMD HDMI audio regression.

Also, this issue only affects the HD Audio HDMI codec driver for AMD/ATI hardware when using PulseAudio or PipeWire. Accessing raw via ALSA and using direct audio output is not affected by this Linux 6.1 regression, nor does this bug affect Intel and other codecs as they have arbitrary connections between pins and converters.

Takashi Iwai, maintainer of the Linux sound subsystem at SUSE, describes the details of the bug in this commit, along with details of the latest HDMI codec driver refactoring. He submitted a fix in the kernel mail, which will soon be backported to the Linux 6.1 stable series, and the bug will be fixed in the upcoming Linux 6.1+ minor releases.