Isochronous USB Issues » History » Revision 2
Revision 1 (laforge, 01/07/2022 07:18 PM) → Revision 2/24 (tnt, 01/07/2022 07:23 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|
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.