DisplayLink doesn't work when intel_iommu is enabled

geostar1024 · 05-05-2019, 06:14 PM

I've run into the same issue on both 16.04 and 18.04, with the latest version of the driver (5.1.26). I've tried various combinations of kernel parameters, but end up with the same error in dmesg whenever I try to activate a DisplayLink adapter:

DMAR: Allocating domain for evdi.0 failed

It looks like the driver isn't handling DMA correctly or something like that. Since it seems like the odds of someone wanting to pass one of these adapters through to a VM is quite low (considerably lower than simply wanting to have virtualization active), I'd suggest that the fix be to simply disable iommu capability in the driver until a better fix can be devised.

05-05-2019, 06:14 PM	#1
geostar1024 Junior Member Join Date: May 2019 Posts: 4	I've run into the same issue on both 16.04 and 18.04, with the latest version of the driver (5.1.26). I've tried various combinations of kernel parameters, but end up with the same error in dmesg whenever I try to activate a DisplayLink adapter: DMAR: Allocating domain for evdi.0 failed It looks like the driver isn't handling DMA correctly or something like that. Since it seems like the odds of someone wanting to pass one of these adapters through to a VM is quite low (considerably lower than simply wanting to have virtualization active), I'd suggest that the fix be to simply disable iommu capability in the driver until a better fix can be devised.