Linux Thunderbolt Support Can Work On Arm Systems

While there aren't yet any Arm SoCs we are aware of at least offering Thunderbolt connectivity, that will eventually change with at least USB4 being based on Thunderbolt. But in any case Thunderbolt software support can work on Arm today if using a Thunderbolt add-in PCIe card.

Queued for Linux 5.8 is the change to allow Intel's Thunderbolt driver code to be built on non-x86 platforms.

The one line patch removes the artificial limitation in the Kconfig build setup that put the Thunderbolt code contingent on an x86-based kernel when in fact there are apparently no x86-isms within the driver code.

Testing was done with the SolidRun HoneyComb Arm workstation while using a Gigabyte "Titan Ridge" Thunderbolt 3 PCI Express add-in-card. That card with the Intel JHL7540 TB3 controller ended up working fine from the 16-core Cortex-A72 Arm workstation on Linux, once building the Thunderbolt kernel support by addressing the Kconfig blocker.

Now with this pending Thunderbolt change for Linux 5.8 it will be easy for others to also build an Arm Linux kernel with Thunderbolt support enabled.