Re: [RFC PATCH] usb/acpi: Add support usb port power off mechanism for device fixed on the motherboard

Peter Stuge
2012-05-15T04:57:48Z

Sarah Sharp wrote:
> > > Theoretically there's no maximum number for xHCI root ports
> >
> > Hm? Please clarify this?
> >
> > HCSPARAMS1 MaxPorts is 8 bits and "Valid values are in the range of
> > 1h to FFh."
>
> Sorry, yes, you're correct, the maximum number of ports for xHCI is 255.

Thanks for confirming!

> I was just trying to point out that it's possible that xHCI hosts will
> have a much larger number of USB ports than what we've previously seen
> on EHCI host controllers.

Yep, absolutely. I was just worried that I had missed something.

//Peter