I am working on a project which utilises 18 high-end DSLR cameras, connected to a PC via USB.
During development the system was running USB2 will no problems whatsover but when we moved to a system running USB3.0 we started getting the following error which resulted in only 11 of the cameras being recognised.
The configuration is that the cameras connect to a powered USB3 hub (something like this) which allows 7 devices to be attached. The system has three of these – all powered, but will only support around 11 of the connected devices (two and a bit hubs worth). We are sure that this is a power issue but all of the hubs are powered and the cameras are also on mains adapters.
At the moment we are having to fall back to USB2 but the transfer rate means that the photo capture process has increased significantly – each image file is around 23MB and it can take 20 seconds or so to download all of the files.
I'm hoping that there is a way around this limitation with the Intel hardware – another driver or a different controller altogether.
Thanks in advance
Best Answer
There is a hardware limit of 96 endpoints on most Intel XHCI controllers. It wouldn't surprise me if each camera is using 8 endpoints, that's a pretty typical number for complex, modern devices. The hubs occupy endpoints as well. You can confirm this with USBView. This is a controller hardware limitation, and there's no way around it.