On Wed, 28 May 2014, Leandro Liptak wrote:

> > If you comment out the pci_write and plug in a USB device, like a flash
> > drive, does it work okay?
> >
> > Have you checked for any BIOS updates available from the manufacturer?
> > This really sounds like a bug in the BIOS.
> 
> Yes, any plugged USB device seems to work ok! I didn't find any BIOS
> update.. So I don't know if this line of code is really necessary at
> all, perhaps it could be a configuration option at kernel compilation
> time (?)

It really is necessary.  It is documented in section 5.1 of the EHCI
specification.  If your computer hangs then your computer is not
compliant with the spec.  This is undoubtedly caused by a BIOS bug.

What happens if you initialize try_handoff (at the start of the 
functionn) to 0 instead of 1, and leave the pci_write unchanged?

Also, can you post the output from dmidecode?

Alan Stern

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