SteamOS should by default have the kernel boot param 'thunderbolt.host_reset=0'

[calebadavis]

In the absence of the kernel boot param 'thunderbolt.host_reset=0', no external USB4 or thunderbolt drive can host the SteamOS boot partitions. Making this easier for users out of the box seems like very low hanging fruit for Valve, and would open up a lot of possibilities for less technically savvy users to be more flexible with how they use the OS on a wider range of hardware.

It's not terribly difficult to get this working today, by tweaking /etc/default/grub-steamos and whitelisting the change, but I can't think of a good reason to force users to go on this sort of spelunking trip through the guts of the OS, instead of making it the out-of-the-box default behavior.

[kisak-valve]

Hello @calebadavis, this reads like something that should be reported to and evaluated by the thunderbolt subsystem maintainers of the Linux kernel and should be improved for everybody using hardware similar to yours regardless off distro choice.

[calebadavis]

@kisak-valve possibly, but I'm going on the assumption that far smarter developers than me have good reason for this behavior (I imagine a much wider range of usb4/tb devices than just external drives likely need to be initialized when the kernel loads). To be clear, I know virtually nothing more on this topic. I discovered this issue by chance when I wanted to try out steamos without nuking my main boot drive, and once I found the workaround, decided to report it here to Valve as a courtesy. The onus is now on you to weigh if you should ignore it, or take a win on the trivial amount of effort it would take to implement this in your out-of-the-box config files. I highly recommend you go with the latter, and improve your product for your users, instead of just passing the buck upstream. I won't be engaging again on this topic.