NEC Chipset cardbus USB2 card not working in high speed mode - any hints?
James Wilkinson
james at westexe.demon.co.uk
Wed Dec 15 13:14:00 UTC 2004
Charles E Taylor IV wrote:
> There's only two ports on this card, and both work at high speed on Fedora
> Core 1 (and for that matter, Redhat 9). Neither port works at full speed
> on Fedora Core 3, and both give the same "ehci_hcd fatal error" message.
Can I just note that when USB 1 was brought in, "full speed" was defined
to be 12 Mbit/s (which was full speed for those devices). The 480 Mbit/s
that USB 2 can provide was, years after USB1 was specified, called "high
speed" (or "hi speed").
And "full speed" was not redefined: to this day, it remains 2.5% of what
a USB 2 port can do.
And so you can get full speed USB 2 devices that only do 12 MBit/s.
I've no idea whether this has any bearing on the original problem...
James.
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