(Maybe to be moved to misc@) Dear OpenBSD tech@,
Thunderbolt support would be awesome. Especially it would allow the use of additional M.2 NVMe SSD:s on a laptop at full performance. Thunderbolt support would also allow the use of an AMDGPU via a PCIe chassi, as well as enable the use of 10gbps Ethernet on laptops [1]. While I like to use Thunderbolt for this pragmatic reason, also Intel apparently promises license etc. generosity to computer makers, which certainly does not hurt. [2] FreeBSD has Thunderbolt support. It appears to me that they call it "PCIe Hot plug". [3] It was implemented 2015 by John-Mark Gurney <j...@freebsd.org>. Not sure if a TB device must be attached on boot and cannot be detached, anyhow if that is the case then still totally fine. NetBSD appears to have support also but I don't find details. Security-wise Thunderbolt without IOMMU is correlated with physical break-in attack vectors, anyhow that is commonly fine. [4] One Thunderbolt 3 controller provides 22gbps of PCIe data bandwidth to all the one or two Thunderbolt ports it exports, which is fine. [5] Many Thunderbolt devices allow daisy chaining. An "eGFX" certified [6] Thunderbolt PCIe chassi (such as [7]) has absolutely no performance advantage over a normal Thunderbolt PCIe chassi (such as [8]), including for eGPU (e.g. AMDGPU) use. Joseph [1] The lowest cost and most common 10gbps Ethernet Thunderbolt chip is Aquantia AQC107S. There are also some adapters based on a normal PCIe 10gbps chip and a separate Thunderbolt to PCIe controller. [2] https://www.theregister.co.uk/2017/05/24/intel_thunderbolt_3forall/ [3] https://www.freebsd.org/news/status/report-2015-01-2015-03.html#Adding-PCIe-Hot-plug-Support https://www.freebsd.org/news/status/report-2015-07-2015-09.html#Adding-PCIe-Hot-plug-Support [4] https://www.osnews.com/story/129501/thunderbolt-enables-severe-security-threats/ [5] And not 40gbps as common marketing makes it sound like. [6] https://thunderbolttechnology.net/egfx https://thunderbolttechnology.net/blog/the-difference-between-egfx-and-egpu = marketing mumbo jumbo. [7] https://www.asus.com/Graphics-Cards-Accessories/XG-STATION-PRO/ [8] https://www.akitio.com/expansion/node-pro
