Device working on USB 2 but not on USB 3, best way to isolate the problem

[Hans Petter Selasky]

On Saturday 30 June 2012 11:46:10 Erich Dollansky wrote:
> Hi,
> 
> I have here a several  storage devices which all work in different FreeBSD
> machines on USB 2. Some of them also work on an USB 3 port but most fail.
> 
> Even one USB 3 device works on USB 2 but not on USB 3.
> 
> As at least two USB 2 devices work both on USB 2 and USB 3, I expect the
> USB 3 port of the computer to work properly.
> 
> I did some trial and error testing but could not get a clear picture.
> 
> What would be a good strategy to find out the difference which causes the
> failure?
> 

Hi,

You can try to look at the Linux XHCI driver, and the port switching support 
they have. It appears that because many old OS'es does not support USB 3.0 out 
of the box, mainboards come with EHCI + XHCI and this requires some magic bit 
fidling, which is not in the FreeBSD XHCI driver.

My best quess.

--HPS