AMD RX 550 Audio Passthrough of 8 channel sources

    LE 9.2.3, x86_64

    I just replaced my GT 1030 with an RX 550 to get HEVC HW acceleration.

    The video works great but now I have an audio problem.

    HDMI audio passthrough of everything works *except* DTS-HD and TrueHD. Which is of course most of my sources. Worked flawlessly with the GT 1030, so I know it isn't a receiver (Denon x6500h) or cable problem.

    The symptoms are exactly the same as 101900 – No HDMI HBR audio on Polaris (no TrueHD, no Atmos, no Neo:X, no HD Master audio) and static noise in sound when LPCM on amdgpu Xorg driver where the EDID information for amdgpu was reporting 7 speakers instead of 8 for a 7.1 receiver--except that this was supposedly fixed in the kernel just over 2 years ago.

    Could this be a regression in the kernel? Known issue? Something else? I'll try to figure out how to collect the right logs and report it, but I've not done that before, so I'm curious if anyone is using AMD RX or newer and seeing similar symptoms that might be able to point me in the right direction.

    Thanks!

    Progress?

    I was able to get passthrough of all codecs working with a modprobe.d file containing:

    Code
    options snd_hda_intel snoop=1

    That immediately got everything functional.

    But now, the keyboard clicks all have an echo, sometimes they repeat once or twice, sometimes five or six times, and when I do start a video, I get horrible clipping.

    I've tried all of the other snd_hba_intel settings I could find for position_fix, enable_msi, power_save, to no effect.

    Does anyone have any ideas for what to try next? I'm not sure if I'm looking at an snd_hda_intel issue, an alsa issue, or an xbmc issue.

    Thanks!