Does anyone get AMD books USB x2 link?
for example USB4 20Gbps x 2
or USB 3.2 Gen2 x 2
I always get x1 connections, with known good cable and USB3.2 gen2x2 and USB4/TB4 enclosures.
Example Linux kernel log connecting ASM2464 (USB4/TB4 20Gx2) at port No. 4 (USB3.2)
[ 1.672738] usb 2-1: new SuperSpeed Plus Gen 2x1 USB device number 2 using xhci_hcd
[ 1.693528] usb 2-1: New USB device found, idVendor=2d01, idProduct=3666, bcdDevice= 1.00
[ 1.694198] usb 2-1: New USB device strings: Mfr=2, Product=3, SerialNumber=1
[ 1.694790] usb 2-1: Product: USB 3.2 SSD Drive Enclosure
[ 1.695327] usb 2-1: Manufacturer: Gopod Group Limited.
USB3 20G will not be possible, as even AMDs own specs say that they do not support that.
USB4 20G should be possible and should be what is used whenever you connect a USB4 host port with a USB4 device, but the cable connecting them is not Gen 3 / 40 Gbps capable, but only Gen 2 / 20 Gbps capable. Just like it happens on Intel hosts and just like it has been working with TB3.
TB4 is not a connection type. It is a certification for USB4. So the connection type between 2 TB4 devices will always be USB4 or TB3 (or USB3 and slower if the cable supports neither TB3 nor USB4). And Asmedia announced having reached TB4 certification for their ASM2464. But they did not say which firmware version. And since most devices are not getting firmware updates, they might not actually be certifiable.
You asked about there being no USB3 20G support on the FW.
Are you now asking about limited PCIe throughput? Or are you confusing USB4 and USB3? It is not clear to me what your initial question has to do with USB4.
In any way, the PCIe tunnel and PCIe config between ASM2464 and the SSD is very independent from the USB4 or TB3 connection speed.
So when debugging PCIe throughput problems, check the PCIe connection (lanes and speed) the SSD (the SSD itself, not the various TB3/USB4 controllers) is actually attached with. My ASM2464 has been very erratic (like only using PCIe x2 without ANY reason), although mostly on hosts that do not use the Windows USB4 drivers or when behind a TB4 hub.
Other throughput limitations might also apply on top, like the OS being somehow limited.
hmm, bad title, I was to say I can’t get any x2 lanes USB connection, {5,10,20}Gbps x 2 USB lanes. not about PCIe.
I had an Intel 12-gen, which 10Gbps x 2 works with 2364 and 2464, but I can’t access it for now. And my 2 cables are TB4/USB4 whatever 4 40Gbps rated, and tested with TB3 (another older Intel 8-gen), should likely be ok.
You just said boltctl is showing 20Gbps x2, which is a USB4 40Gbps connection, which is using 2 lanes. So you already have the fastest connection that you are going to have. If the actual throughput with the SSD is not satisfactory, that is a different problem. Not one of the USB4 connection.
And it is not really useful to speak about lanes with USB. The overall connection speeds are far better.
USB3 10G
USB3 20G X unsupported by any FW host
USB4 20G ← supported, but why would you want this if you can have 40G
USB4 40G ← you said you have this