A:
The bus master transfer function of our devices and IOMMU function cannot be used together.
In Ubuntu 24.04, the OS default is "intel_iommu=on".
Because of this, in the default state of Ubuntu 24.04, bus master transfers on devices such as DIO-32DM3-PE will not work properly.
If you use the bus master transfer function of our device, please set "intel_iommu=off".
When configuring the following settings, please do this with root privileges on Ubuntu OS.
1. Edit the /etc/default/grub file and add "intel_iommu=off" to the "GRUB_CMDLINE_LINUX" key.
2. Run the update-grub command.
3. Reboot the OS.
( Reference )
IOMMU : Input - Output Memory Management Unit
IOMMU can be used for AGP (Accelerated Graphics Port), PCI Express graphics, etc.