Intel Lands Linux Audio Fix For Arc Graphics A750/A770

If you have been running a Linux 6.3-based kernel or later Linux 6.2 point release and have encountered your HDMI audio breaking when making use of Intel Arc Graphics A750/A770 hardware, a fix is on the way.

Recently there have been bug reports around HDMI audio breaking and a regression compared to older kernel versions. This issue was tracked down and a fix was merged today to Linux 6.3 Git that is also marked for back-porting to the stable kernel series.

The fix is to disable Keep-Alive "KAE" functionality for Intel DG2 discrete graphics. The commit explains:

"Use of keep-alive (KAE) has resulted in loss of audio on some A750/770 cards as the transition from keep-alive to stream playback is not working as expected. As there is limited benefit of the new KAE mode on discrete cards, revert back to older silent-stream implementation on these systems."

Last year this Keep-Alive support was added for Alder Lake P and DG2/Alchemist hardware. The commit at that time explained:

"Implement HDA keep alive (KAE) support for Intel display codecs. When no audio stream is active, the display codec will provide a continuous clock and a valid but silent audio stream to any connected HDMI/DP receiver. Without this, upon starting a new playback stream, initial samples may be lost as many receivers require time to initialize for new clock.

This is a new feature in Intel AlderLake-P display codec implementation and replaces the Intel i915 silent-stream extension that has been used on older hardware. Main benefit of the new method is that codec no longer needs to be kept in D0 power state."

So with KAE now disabled for DG2/Alchemist hardware, there hopefully are no more HDMI audio troubles under Linux with these Arc Graphics discrete GPUs.