On Tue, 22 Mar 2022 19:57:27 +0100, Jason Andryuk wrote: > > Hi, > > I'm running Xen hypervisor and using PCI passthrough to assign an > Intel HDA audio device (00:1f.3 Audio device: Intel Corporation Cannon > Point-LP High Definition Audio Controller (rev 30)) to a Xen HVM > virtual machine. I do this for both Linux 5.4.185 and a different > Windows 10 VM (only one at a time). The Windows VM seems to work > every time. The Linux VM has issues after the first VM boot. This is > one boot of the physical hardware and multiple boots of the virtual > machines. > > For Linux, on first boot, the sound card is detected and works > properly. After that, things usually don't work. I just ran a reboot > loop and it was: > 1st boot - audio detected and working > 2 & 3 - no audio > 4th - audio detected and working > 5 - 20 - no audio > > For boots 2, 3, 5-7, dmesg shows: > [ 0.760401] hdaudio hdaudioC0D0: no AFG or MFG node found > [ 0.760415] snd_hda_intel 0000:00:06.0: no codecs initialized > > For boots 8+, the errors changed to: > [ 0.783397] hdaudio hdaudioC0D0: cannot read sub nodes for FG 0x10 > [ 0.783413] snd_hda_intel 0000:00:06.0: no codecs initialized > > At this point, I booted a Windows 10 VM and audio works > > Trying to boot Linux again gives a new error message > [ 0.789041] snd_hda_intel 0000:00:06.0: Unknown capability 0 > [ 1.811205] snd_hda_intel 0000:00:06.0: No response from codec, > resetting bus: last cmd=0x0eef0004 > [ 1.811246] hdaudio hdaudioC0D0: cannot read sub nodes for FG 0x10ee > [ 1.811263] snd_hda_intel 0000:00:06.0: no codecs initialized > > Reboot VM and it's back to: > [ 0.775917] hdaudio hdaudioC0D0: no AFG or MFG node found > [ 0.775932] snd_hda_intel 0000:00:06.0: no codecs initialized > > Reboot VM and again: > [ 0.789069] hdaudio hdaudioC0D0: cannot read sub nodes for FG 0x10 > [ 0.789084] snd_hda_intel 0000:00:06.0: no codecs initialized > > Reboot physical laptop: > 1. boot Windows 10 - audio works > 2. boot Linux - audio works > 3. reboot Linux - no audio > [ 0.773111] hdaudio hdaudioC0D0: no AFG or MFG node found > [ 0.773151] snd_hda_intel 0000:00:06.0: no codecs initialized > > This seems to me like Windows does a better job resetting the card to > get the audio hardware working. Any suggestions on what to > investigate? First off, 5.4.x is way too old to debug, please confirm the issue with the latest kernel. And, one test I'd try is to unload snd-hda-intel module before rebooting. Does the problem persist? Takashi
