[Issue]platform/x86: iommu: System can't shutdown because iommu driver keeps checking the status of DMA_GSTS_TES

[Koba Ko]

hi All,
I have a machine and there's only intel gpu.
the secureboot and vt-d is enabled in BIOS.
On the Ubuntu desktop, I do s2idle first and restart the machine.
The machine can't restart successfully, so I need to press the power
button to shutdown.
I tried  each of the following and the issue can't be triggered.
1. disable secure boot in BIOS.
2. intel_iommu=off.
3. intel_iomm=igfx_off.
4. nomodeset
5. i915.modeset=0.

After I investigate further, find inte_iommu keeps checking the status
of DMA_GSTS_TES.
During the procedure of restart, the driver would disable iommu translation and
check the status of DMA_GSTS_TES until status of DMA_GSTS_TES is 0.

If you need more information, I can provide it.

Thanks
Koba Ko