Allegro USB-C 4-Port PCIe Card (USB3C-4PM-E)
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FAQ (11)
IDArticle TitlePost Date
756 Do the Sonnet USB 2.0 or USB 3 cards support the Apple SuperDrive?Apr-02-22
759 My bus-powered USB 3 drive or SSD will not reliably mount or transfer data.Dec-14-19
817 Storage connected to a USB 3 PCIe card (or Tango combo card) gives an macOS error message upon wake from sleep.May-12-20
933 What versions of macOS support Allegro USB 3 cards?Apr-02-22
956 What generations of Thunderbolt chassis do Sonnet Allegro PCIe cards support?Apr-02-22
971 One or more of my ports has stopped working on my USB 3 card.Aug-24-22
1080 What is the difference between USB 3.0, 3.1 and 3.2?Apr-02-22
1099 What makes Sonnet USB 3.2 Cards more reliable than other USB 3 cards?Apr-02-22
1144 Why does Sonnet use only PCIe 2 to connect the two controllers on these 4-port USB 3.2 Gen 2 cards?Apr-18-21
We connect each USB 3 controller with two lanes of PCIe 2. Each controller has 1000MB/s bandwidth which is enough bandwidth for the fastest devices you can connect, such as USB 3.1 Gen 2 NVMe SSDs. Because the read/write bandwidth is independent, on one controller you can be reading from one SSD at 1000MB/s, and writing to another at 1000MB/s, plus the same on the 2nd controller for an aggregate transfer rate of 4000MB/s. What makes this possible is that Sonnet uses the advanced ASMedia 3142 Controller that supports Multiple INs, which means that reads can commence on one port before a write has competed on the other port.

A PCIe 3 Bridge chip would cost you $50 more, but would give you incremental performance only if you needed to continually simultaneously read--or simultaneously write--to four USB 3.1 Gen 2 NVMe devices, a very unusual use case.

 
1149 How to configure Linux to use Allegro Pro USB card models USB3C-4PM-E and USB3-PRO-4P10-EMay-04-21
In some computers, USB 3 devices connected to Allegro Pro USB 3 card models USB3C-4PM-E and USB3-PRO-4P10-E are not detected by Linux.

You can fix this by adding the Linux kernel parameter pci=disable_acs_redir=pci:12D8:2308 to the computer's Linux boot script. (Describing how to add a Linux kernel parameter to the computer's Linux boot script is beyond the scope of this FAQ.)

This parameter sets disable_acs_redir for PCIe devices with id 12D8:2308 (which is the PCIe bridge chip on these cards). This parameter disables PCI Express Access Control Services (ACS) functions ACS P2P Request Redirect and ACS P2P Completion Redirect. This has no effect on operation unless you are in a virtualized environment, in which case you must assign all four USB 3 ports to a single virtual machine.
 
1168 If I put a usb 2.0 and 3.0 device on the same controller will the speeds for the 3.0 device drop to 2.0 like older split-port controllers?Dec-07-21
The Sonnet Allegro USB-C and Allegro Pro 4-port Type A USB 3.2 cards support the fastest speed of each device independently on each port. The Sonnet cards supports "Multiple Ins", which means that that the host can issue a read request to one endpoint device and then proceed with other transactions without waiting for the response from the first device. Supporting Multiple Ins also improves performance to mutiple Gen 1 devices on a downstream Gen 2 hub connected to a Sonnet card Gen 2 port.