[vfio-users] Fwd: [vfio/qemu] Pass-through non-resettable HDA controller

[Mike Pozulp]

Forwarding to the vfio-users at redhat.com mailing list which I just
learned about. I think this mailing list is exactly what I needed. :)
-Mike P

---------- Forwarded message ---------
From: Mike Pozulp <pozulp.kernel at gmail.com>
Date: Mon, May 25, 2020 at 11:53 PM
Subject: [vfio/qemu] Pass-through non-resettable HDA controller
To: <alex.williamson at redhat.com>


Hi Alex,

I own a 2019 Samsung Notebook 9 Pro that refuses to send audio out the
speakers on Linux. The speakers work great in Windows 10. I reported
Bug 207423 in the kernel bugzilla. Jaroslav Kysela suggested that I
dump the communication between the HDA controller and the audio codec
using vfio with qemu. I am able to get a trace for resettable devices,
like the USB controller, but when I passthrough the non-resettable HDA
controller to qemu the only output I see is

qemu-system-x86_64: vfio: Cannot reset device 0000:00:1f.3, no
available reset mechanism.

Is qemu refusing to pass-through the HDA controller because qemu fails
to reset it? Does qemu have a do-not-reset-devices option? Am I stuck?

Thanks for all your hard work on vfio! I really appreciate it =)

Kernel bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=207423
Arch forum: https://bbs.archlinux.org/viewtopic.php?pid=1906657

Best,
Mike Pozulp