If igfx_off is default, how / why is it on?
from
https://www.kernel.org/doc/html/latest/admin-guide/kernel-parameters.html
"...
intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
on
Enable intel iommu driver.
off
Disable intel iommu driver.
igfx_off [Default Off]
By default, gfx is mapped as normal device. If a gfx
device has a dedicated DMAR unit, the DMAR unit is
bypassed by not enabling DMAR with this option. In
this case, gfx device will use physical address for
DMA.
...
On Sat, 3 Jul 2021 at 01:25, Bryan Cebuliak <bryan.cebul...@gmail.com>
wrote:
> more possibly relevant IOMMU video audio and passthrough issue links:
> Easy ACS kernel patch guide for Ubuntu 20.04
> https://www.youtube.com/watch?v=JBEzshbGPhQ
>
>
> https://forum.level1techs.com/t/intel-graphics-hdmi-audio-fails-after-enabling-intel-iommu-on/168827
>
> kvm-gpu-passthrough-on-debian-buster.md
> https://gist.github.com/davesilva/445276f9157e7cb3a4f6ed2fe852b340
>
>
