Hi
Am struggling to get : 2 gpus working with my x399 mobo.
My 2 gpus are Titan Volta and RTX 2089
At first was getting a Code OE on boot and couldn’t even make it to BIOS.
Then tried swapping card slots so TitanV in slot 4 and 2080 in slot 1.
Making progress but after Ubuntu grub menu I now get repeated Bad DLLP and TLP errors.

Some googling came across one thread that suggests altering the Linux kernel on boot.
My question is which of the following 2 options are preferred and is there any danger with either option?

1) Disable Message Signalled Interrupts (MSI) in the kernel with pci=nomsi option. This however, also disables MSI for all other devices so may be less than optimal.
2) Disable MMCONFIG (MMIO access method to PCI configuration space) in the kernel with pci=nommconf. I don't understand this enough to say what kind of drawback this has, but it is a way to workaround the PCIe bus errors while keeping MSI (option #1 above) enabled for other devices.