Devices change their IOMMU groupings with kernel upgrade?

[CommandLionInterface]

Ok so this is really weird: Before, I was able to pass through my motherboard's HD Audio to a virtual machine just fine. Now, I upgraded to 6.2.0-rc4 and suddenly it throws the IOMMU error. Checking the devices, it appears as through HD audio is in fact in the same IOMMU group as my onboard NIC and several other onboard devices. Could the update to kernel 4.4.18 have caused this change? I wasn't aware software had any control over this at all.

 

Any ideas what to do then?

[Squid]

http://lime-technology.com/forum/index.php?topic=51322.msg493144.msg#493144

 

Sent from my LG-D852 using Tapatalk

 

 

[CommandLionInterface]

http://lime-technology.com/forum/index.php?topic=51322.msg493144.msg#493144

 

Sent from my LG-D852 using Tapatalk

 

Lol didn't see that. Thanks.

 

For the curious:

 

The problem is that a bug fix in the kernel indirectly "broke" Skylake onboard audio pass through.  In Skylake, Intel put the onboard audio in the same IOMMU group as the SMBus controller.  A kernel bug prevented this SMBus controller from being recognized correctly, thus preventing assignment of the SMBus driver.  But once this bug got fixed, we now have a situation where a device in an IOMMU group has a kernel driver assigned, preventing it, and any other device in the same IOMMU group from being assignable to a VM.  Hence, for Skylake, onboard audio passthrough was working "by accident" in 4.4.17 and below