I am looking to dual boot Fedora 40 with Windows 11 on a Dell XPS 13. I have reading conflicting advice about the need to disable RST before installing Linux. This is the information provided by Ubuntu.
Can anyone tell me whether I need to disable raid before installing Fedora? I have managed to boot Fedora 40 from USB without any difficulty.
Depending upon the hardware and the version of fedora being installed it may be necessary to disable rst. It also may be necessary to switch the sata settings from RAID to AHCI. This is up to testing to determine which is required.
Some open the bios settings and make the switch then boot into windows to ensure that windows can still boot (and make repairs if needed) before installing fedora.
You’ll very likely have to, but if you want to know for sure, leave it enabled and boot a Linux LiveUSB, and see if you can see drive(s).
In my case with Coffee Lake, my NVMe doesn’t show up at all with RST enabled and dmesg shows something about port remapping. There’s probably something to make it show with RST enabled, but it was determined by someone with reason(s) to make it not appear by-default, and RST does nothing beneficial in this set-up since it’s still AHCI; hence disabling it and going with AHCI makes sense 
I had a XPS 13 at some point and also went with using AHCI Windows and Linux.
Also with my NVMe currently, using RST only allows the NVMe to be visible at all when it’s in 512e sector mode. When it’s on native 4K sector mode, not even BIOS sees it with RST. That implies RST (at least on my set-up) is for Legacy applications.
I can do 4K sectors fine Windows and Linux with AHCI.
Yo do need to disable raid, but if Windows was installed with raid, you need to reconfigure it to boot with AHCI before disabling raid in “BIOS”:
You don’t need to disable VMD/RST to dual boot Fedora and Windows 11. I dual boot them with VMD and RST on all the time.
I wonder what determines whether NVMe is shown with the remap? Between openSUSE, Ubuntu, and Fedora, there were differences if RST was enabled (vs AHCI) and whether my NVMe would be visible or not, but FreeBSD saw it fine both ways.
There was a hint in dmesg implying the NVMe got disabled because it was detected in the remap mode, implying there’s a way to disable that from happening (I’m not sure why it’s enforced to hide remapped NVMe/drives by-default).
Really simple to understand.
Early versions of the intel RST hardware were not supported at all by fedora and the drives could not even be seen unless the bios was set to AHCI mode. Later versions of the RST have resolved this.
Both hardware and software are constantly evolving.
That didn’t really explain anything technical 
I have Coffee Lake which I’m thinking is pretty mature for RAID oproms/etc. Windows and FreeBSD today handle NVMe AHCI or RAID options and present my drive no problem.
If it was a years-old decision to blanket-cover all devices no matter what under remap, I’m thinking that probably should be re-worked in order to avoid people running into hidden drives with default RST/RAID as it doesn’t seem necessary to still be doing today.
I’m pretty sure there’s other Linux distros that don’t auto-hide remapped drives before install, but I’d have to back-to-back some LiveUSBs to check latest releases.
I can understand Windows’s support, FreeBSD just does it, so I’m thinking Linux can do it too
Is the thing that hides remapped devices behind a kernel parameter?