On Wednesday, March 20, 2019 at 8:33:27 AM UTC-4, [email protected] wrote:
> Hello qubes users!
> 
> I currently acquired this dock 
> (https://www.dell.com/en-us/shop/dell-business-thunderbolt-dock-tb16-with-240w-adapter/apd/452-bcnu/pc-accessories),
>  and tried to connect it with my laptop, but it does not seem to work.
> 
> I have found different posts here and there regarding the issue, and I think 
> the most common solution is turning on the computer with the cable attached. 
> This does NOT work however.
> 
> I have not tried to boot up without attaching, and viewing lspci output, and 
> then comparing to when I have it connected. Will do that and post back if 
> there are no better suggestions for now.
> 
> I have also NOT modified my kernel yet or done anything to the start up flags 
> (other than enabling USB devices in general, so I can use my keyboard and 
> mouse).
> 
> I am running Qubes 4.0.
> 
> Any help appreciated!
> 
> Best regards!

So there are 3 things I needed to do to get Thunderbolt docks to work on a 
laptop with Qubes:

1) Disable Thunderbolt device authorization in the laptop BIOS since we need 
the device to be online when Qubes is booting, rather than waiting for the OS 
to come online enough to authorize the device. If you had a Dell laptop some of 
them have an option to treat Dell docks differently which you may be able to 
use instead.

2) Have the dock plugged in and awake when Qubes is booting. Note that when 
booting from a cold shutdown you may need to connect the dock *after* the 
motherboard is powered on, but *before* the kernel boots -- one dock I tried 
needed this to wake up correctly and be awake before the kernel initialized PCI 
devices.

3) Manually add and remove PCI devices provided by the dock from individual 
Qubes (e.g. sysnet and sys-usb). The Qubes will no longer boot once the PCI 
devices are not present after you unplug the dock, but at the same time they 
can't be connected to the Qubes after boot since they don't have hotplug 
enabled. So when you get to your desk you'll need to reboot the laptop, then 
attach the PCI devices to sys-usb and sys-net, then restart those Qubes. 
Restarting sysnet and sys-usb often results in broken tray icons, so at that 
point you may also need to reboot the laptop (you can leave the dock connect 
during this IME). After you leave your desk you'll need to boot without the 
dock, remove the now-missing PCI devices from sys-net and sys-usb, and then 
reboot again to get everything working again.



You're doing all this, BTW, because rather than supporting Thunderbolt and PCIe 
hotplug (which are usually protected by that device authorization you have to 
disable), Qubes is trying to protect users with FireWire and ExpressCard that 
are fundamentally insecure. I hope those extra 4 times a day you enter your 
dom0 decryption key on boot while using a dock aren't putting that key at extra 
risk or incentivising you to use a weaker key. :(

More broadly, I think the lack of hotplug support is a misguided trade-off that 
hampers the usability of Qubes and just creates one more barrier to adoption 
for users. Folks with firewire ports/expresscard slots and nation-state 
adversaries with physical access need to disable those ports/slots in BIOS 
rather than relying on lack of hotplug support to protect them. It's not that 
hard to hide something in an expresscard slot that will be there on boot, and 
then it's game over for dom0 even without hotplug.

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