Thunderbolt docking station and RHEL 7.3
Good evening
I have some issues with a thunderbolt docking station [HP ZBook Dock with Thunderbolt 3] (http://www8.hp.com/us/en/workstations/zbook-dock.html) and RHEL 7.3.
The problems are different: the worst is system hang (!). Furthermore every 2 /3 seconds the secondary monitor connected on docking turning itself off and on, and the usb keyboard occasionally refuse to work. Peripherals like the docking network adapter or external usb disks apparently work the correct way. Using fedora 25 the situation improves significantly and docking becomes usable. With ms windows no problem.
On the manufacturer's site I did not find anything except: "As of this edition, the docking station has not been tested for compatibility with Linux distributions. New information becomes available over time. " [Linux Hardware Matrix for HP Workstations] (http://h10032.www1.hp.com/ctg/Manual/c00060684.pdf)
There is some way to use this device with RHEL7.3? Is there a guide ( or suggestions ) to thunderbolt troubleshooting?
Thanks in advance
Responses
On non-Apple devices, the Thunderbolt in general is usually handled by ACPI, so make sure your firmware is up-to-date and you have the ACPI PCI hotplug module loaded.
With Thunderbolt 3 specifically, a new factor comes into play: the USB Type-C Connector System Software Interface, or UCSI for short: http://www.intel.com/content/www/us/en/io/universal-serial-bus/usb-type-c-ucsi-spec.html
USB Type-C connectors need two new things negotiated when establishing a connection: the USB Data Role (which one is the host and which one is the device) and the Power Role (source or sink). In Linux kernel version 4.9.*, there is a new kernel module ucsi.ko, which will handle this for systems that are always supposed to be the USB Host, i.e. most regular servers and desktops. On laptops, something more might be needed to allow charging the laptop through the USB Type-C connector (assuming the hardware supports that), but at least the ucsi.ko would allow the use of the port for the usual purposes.
On my Fujitsu laptop with a Thunderbolt 3 connector, I tested it by buying a cheap USB Type-C to USB3 Type-A adapter (from Apple, since it was the cheapest such adapter immediately available to me at the time). When using the 4.4.* kernels that don't yet have the ucsi.ko module, the connection was unreliable: I think it was sort of similar to what you're seeing. When I updated the kernel to 4.9.* series and added the ucsi.ko module in my kernel configuration, the port+adapter can now be reliably used as a regular USB3 port at least. I don't have any device that could be used to test the actual Thunderbolt part of the connection (i.e. would be an external PCIe device).
Fedora 25 seems to have the 4.10.* kernel now, so it would include the ucsi.ko module. That might well explain why the situation improves with that.
On RHEL 7.x, I'm afraid your options are either to compile a custom kernel for you, try and backport the ucsi.ko module for the RHEL 7.x standard kernel yourself, or wait and hope that RedHat will backport that module (perhaps for RHEL 7.4?).
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