Cheap x79 chinese mobo: Huananzhi x79-8d bifurcation trouble

[wongdg]

Even though it is obvious the AMI BIOS of this chinese mobo has some kind of PCIE3.0 bifurcation support. I tried inserting a x16 bifurcation card with 4xNVMe (WD SN570) and it showed only 1 NVMe (“Sandisk Corp WD Blue SN570 NVMe SSD”) when mobo bifurcation was at x16, and when mobo bifurcation was set to x4x4x4x4, only 1 “Sandisk Corp Device 501a” came out. Help or pointers needed.

I had tried the above bifurcation card on another mobo of mine (Supermicro x9srl) on a PCIe slot x16physical x8eletrical and indeed in OS I could see 2 NVMe’s showed up ready.

NUMA = enable
IOH0                  IOH1
x8                      x8   
x16                    x16 
x16                    x16 

# lspci -vt

\-[0000:00]-+-00.0  Intel Corporation Xeon E7 v2/Xeon E5 v2/Core i7 DMI2
             +-01.0-[01]----00.0  Sandisk Corp WD Black 2018/SN750 / PC SN720 NVMe SSD
             +-02.0-[02]----00.0  Sandisk Corp WD Blue SN570 NVMe SSD
             +-03.0-[03]--

case:
NUMA = enable
IOH0                       IOH1 
x4x4                       x4x4 
x4x4x4x4               x4x4x4x4
x4x4x4x4               x16  (for nvidia graphic card support)   

\-[0000:00]-+-00.0  Intel Corporation Xeon E7 v2/Xeon E5 v2/Core i7 DMI2
             +-01.0-[01]----00.0  Sandisk Corp WD Black 2018/SN750 / PC SN720 NVMe SSD
             +-01.1-[02]--
             +-02.0-[03]----00.0  Sandisk Corp Device 501a
             +-03.0-[04]--

# lshw | grep -i chip
             product: C600/X79 series chipset PCI Express Virtual Root Port
             product: C600/X79 series chipset USB2 Enhanced Host Controller #2
             product: C600/X79 series chipset High Definition Audio Controller
             product: C600/X79 series chipset PCI Express Root Port 1
             product: C600/X79 series chipset PCI Express Root Port 3
             product: C600/X79 series chipset PCI Express Root Port 4
             product: C600/X79 series chipset PCI Express Root Port 6
             product: C600/X79 series chipset USB2 Enhanced Host Controller #1
             product: C600/X79 series chipset LPC Controller
             product: C600/X79 series chipset 6-Port SATA AHCI Controller
             product: C600/X79 series chipset SMBus Host Controller
# lshw | grep -i smbios 
 %filtered%
       vendor: HUANANZHI
       physical id: 0
       version: VAA31
       serial: MB-xxxxxxxxxxx
     *-firmware:0
          description: BIOS
          vendor: American Megatrends Inc.
          physical id: 0
          version: 4.6.5
          date: 03/28/2019
          size: 64KiB
          capacity: 6MiB
          capabilities: pci upgrade shadowing cdboot bootselect socketedrom edd int13floppy1200 int13floppy720 int13floppy2880 int5printscreen int9keyboard int14serial int17printer acpi usb biosbootspecification uefi

 

[wongdg]

The above x4 lane worked when I configured BIOS chipset bifurcation settings as below:

IOH0 PCIe Port Bifurcation Control	IOU1 – PCIe Port [x4x4] = Port 1A, Port 1B
	IOU2 – PCIe Port [x16] = Port 2A
	IOU3 – PCIe Port [x4x4x4x4] = Port 3A, 3B, 3C, 3D
IOH1 PCIe Port Bifurcation Control	IOU1 – PCIe Port [x4x4] = Port 1A, Port 1B
	IOU2 – PCIe Port [x4x4x4x4] = Port 2A, 2B, 2C, 2D
	IOU3 – PCIe Port [x16] = Port 3A

IOH0 PCIe port Data Direct I/O Control
Port 0A [Disabled]
Port 1A [Enabled]
Port 1B [Enabled]
Port 2A [Enabled]
Port 3A [Enabled]

 

[wongdg]

IOH0 PCIe Port Bifurcation Control	IOU1 – PCIe Port [x4x4] = Port 1A, Port 1B
	IOU2 – PCIe Port [x16] = Port 2A
	IOU3 – PCIe Port [x4x4x4x4] = Port 3A, 3B, 3C, 3D
IOH1 PCIe Port Bifurcation Control	IOU1 – PCIe Port [x4x4] = Port 1A, Port 1B
	IOU2 – PCIe Port [x4x4x4x4] = Port 2A, 2B, 2C, 2D
	IOU3 – PCIe Port [x4x4x4x4] = Port 3A, 3B, 3C, 3D

IOH1 PCIe port Data Direct I/O Control
Port 0A [Disabled]
Port 1A [Enabled]
Port 1B [Enabled]
Port 2A [Enabled]
Port 3A [Enabled]

 

[wongdg]

From the above outcome, I can conclude that
1. the "lowest x16 PCIe slot" is tied to IOH1, which is one of the CPU socket.
2. the so-called bifurcation is a flop

What I am using to test is a non-switched brandless 4x NVMe to PCIe3 x16 adapter card. On the card, its port1 worked when IOH1+IOU3 is set to [x16]. And port4 worked IOH1+IOU3 is set to [x4x4x4x4].