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Hi, doing usb uhci driver and heard that hubs may have more that 2 PORTSC ports. Can anybody confirm that, provide documentation, name of motherboard or usb controller that behaves this way?

Some free source code out there got infinite loops searching for the right port.

Thanks

edited: by 2 ports I mean 2 offsets 10h & 12h + Base IO addr

I believe Linux just tries the ports directly after PORTSCB and increments the port count if some always-on bit is set (bit 9 I think?) then aborts the scan when the bit isn't set or if it exceeds the device's IO range.

I haven't seen any UHCI root hubs that expose more than two ports, so I imagine it's very rare. Usually if a motherboard has more than two USB ports it'll show multiple UHCI controllers on the PCI bus instead of just one.