Isochronous USB Issues » History » Revision 3
Revision 2 (tnt, 01/07/2022 07:23 PM) → Revision 3/24 (tnt, 01/07/2022 07:52 PM)
h1. Isochronous USB Issues It seems there are many XHCI implementations out there that have problems properly computing the isochronous bandwidth limits and hence refuse to activate both [[icE1usb]] interfaces. |_.System/Board|_.USB Controller|_.Runs with 2 icE1usb interfaces| |Raspberry Pi 3B|built-in|YES| |Raspberry Pi 4|VIA XHCI|no| |Thinkpad x260|Intel Corporation Sunrise Point-LP USB 3.0 xHCI CoStroller (rev 21)|no| |PC-Engines APU2|AMD GX-412TC SoC|external:no, internal:YES| |AMD Ryzen|Ryzen CPU|YES| |AMD Ryzen|X570 chipset|YES| |Odroid XU4|USB 2.0 port|YES| |Odroid XU4|USB 3.0 ports|no| Note that in all cases, the device needs to be the sole full speed device on the bus since it uses all the full speed bandwidth and AFAICT all root-hubs are single-TT. It seems that a hub connected to a EHCI/OHCI port works too, but a hub connected to a XHCI port, even one working without hub, doesn't work. (Currently tested only on Ryzen since it's the only working XHCI controller)
