[coreboot] [GSoC] option rom problems with DBM690T+VT6202L

[Stefan Reinauer]

On 7/29/09 3:58 AM, Peter Stuge wrote:
> Note that it is not in fact a UHCI controller if it supports USB 2.0.
> It is difficult (maybe impossible) to find a UHCI PCI card.
>
> An EHCI controller will only and always communicate with high-speed
> devices using EHCI.
>
> The EHCI controller and it's so-called companion controllers do not
> mirror each port. Any connected device will only appear attached to
> one controller, and it will always be the same controller for a given
> device and a given physical port.
>
> In other words, for you to be able to use UHCI with this PCI card,
> you must attach a USB 1.1-only MSC device to one of the ports.
>   
This is interesting, since we have not seen this problem on any Intel
chipset, which have EHCI controllers but do UHCI, too.
It's never been a problem to use the UHCI stack with USB 2.0 capable
devices. Are they doing something special?
I never saw an EHCI only controller, all of them came with either UHCI
or OHCI

Stefan

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