[coreboot] USB problem with Haswell+LynxPointLP motherboards

[Аладышев Константин]

I try to port coreboot on boards with Haswell CPU and Lynxpoint LP chipset
(IBASE IB908AF-4650 board, DFI HU968) and I've encountered a strange
problem. USB devices stop working shortly after OS boot (or after USB device
replug in OS) with flooding system with messages:

hub 1-1:1.0: cannot reset port 5 (err = -110)
hub 1-1:1.0: cannot reset port 5 (err = -110)
hub 1-1:1.0: Cannot enable port 5.  Maybe the USB cable is bad?
hub 1-1:1.0: cannot disable port 5 (err = -110)
hub 1-1:1.0: connect-debounce failed, port 5 disabled
hub 1-1:1.0: unable to enumerate USB device on port 5
hub 1-1:1.0: cannot disable port 5 (err = -110)
hub 1-1:1.0: hub_port_status failed (err = -110)
hub 1-1:1.0: hub_port_status failed (err = -110)

Through some digging I've found out that this problem persist on kernels
<3.5. I've investigated this problem more closely and come down to the fact
that the kernel commit that solves this problem is:

3d9545c EHCI: maintain the ehci->command value properly

https://github.com/torvalds/linux/commit/3d9545cc375d117554a9b35dfddadf9189c
62775?diff=split


And now I'm kinda stuck. The effect of this commit doesn't seem to interface
with bios for me. So how does original IBASE/DFI bios can overcome code
error before this commit?

What can be the source of my problem? What should I investigate more precise
based on result that I've got?