Hello !

 

I'll try to keep it short :

Fresh BigSur install (with Macinabox) on a 256Gb Samsung 980 PRO with the controller passed through.

 

The drive is on now on a PCIe Gen 4 socket but it may important to note that it was (my mistake) on a GEN3 socket during the install.

 

So before I moved it to the right socket, "System Report" reported : Link width : 4x / Link Speed 8GT/s (so GEN 3).

 

Now, it's on the right socket, the lspci command gives : LnkSta:  Speed 16GT/s (ok), Width x4 (ok)

 

BUT, and this is the problem I can't find a solution / explanation for : under System Report, Link Width is still 4x but there is no info for Link Speed...

 

A Blackmagicdesign Disk Speed test shows a read speed of 2.8GB/s (so the same as on GEN3) where the drive is theoretically capable of 7GB/s. And I know I wont get that speed, but now I'm having less than half.

 

Other details :

The same drive passed through (controller) to a windows VM is on a GEN4 link. So all good on this side.

Motherboard is Asus TUF Gaming X570. Latest bios.

The XML part for the controller :

    <hostdev mode='subsystem' type='pci' managed='yes'>
      <driver name='vfio'/>
      <source>
        <address domain='0x0000' bus='0x04' slot='0x00' function='0x0'/>
      </source>
      <alias name='hostdev0'/>
      <address type='pci' domain='0x0000' bus='0x04' slot='0x00' function='0x0'/>
    </hostdev>

 

I even tried to move from Q35-4.2 to 5.1, but nothing changed.

 

My fear is that it's because I swapped socket after the install... And that the solution would be a new install... But maybe one of you will have a better suggestion !

Thanks for your attention.

 

 

Edited May 22, 20215 yr by bjornatic

GNIIiiiiiiiiiiiiiii !!

 

This is me trying to push up this topic. ^^

Edited December 15, 20205 yr by bjornatic

Do you use an nvme.kext?

I use the Nvmefix kext but no other (regarding Nvme).

 

The controller used for the 980 Pro is new (and called Elpis) and i just assumed that i have to wait for a driver / kext update. I was not able to find any one else having this problem with this specific drive.