USB 3.0 support by default?

[Alexander Best]

On Tue Jun 14 11, Hans Petter Selasky wrote:
> On Tuesday 14 June 2011 14:52:08 Alexander Motin wrote:
> > Hans Petter Selasky wrote:
> 
> Done:
> 
> http://svn.freebsd.org/changeset/base/223098

btw., if i might ask a technical and probably naive question:

does USB 3.0 feature *full* backward compatibility? that is supporting usb 1.x
and usb 2.0 devices without the need for enabling those legacy controllers?

so will xhci give me all the backward compatibility or do i have to also enable
a combination of ohci/uhci/ehci? with usb 2.0 there was no usb 1.x support
unless ohci/uhci was also enabled.

i read that the xhci controllers don't depend on CPU and I/O availability as
much as the old controllers. doing CPU intensive tasks shouldn't have such a
massive effect on USB transfer times, compared to usb 1.x and 2.0. that's why
i'd like to completely get rid of the need for ohci/uhci/ehci in my kernel
config.

i'd really like to see some transfer time statistics with CPU being close to
100% idle and with CPU being hammered close to 100% with usb 3.0. i think i did
such a test a while ago for usb 2.0 and transfer rates dropped quite
significantly.

cheers.
alex

> 
> --HPS

-- 
a13x