Privet Konstantin,
Ja mogu i po Russkomu (russkij keyboard ne imeet dlja menja nikakogo smisla perekljucat6, tak cto ja po Russkomu naucilsja davnim, prezde cem (paru let prezde) ZX81 i Spektrum pojavilis6, no budu ja pisat6 po Anglijskij, tak cto ljudi Coreboot-a mogut ponjat6 ob cem mi zdes6 tolkujem/hozjataistvujem. :-)
_______
I do not think that people here, Coreboot people, have appropriate detailed documentation for Lynx Point (Series 8 PCH), which primarily serves to HSW (CORE 4) Family. It also served (as experimental PCH) to some SKL (Core 6) families. Before Sunrise Point (Series 10, I believe) PCH came to existence. About 14+ months ago.
For the bigger picture, I'll suggest to you the following test scenario:
[1] You should do all of this what you have asked here with HSW (CORE 4) true BIOS, and then installing on the top of it any Linux distro (I use Fedora, I mastered it, but you can use any Linux distro of your free choice):
[A] After bringing BIOS up, and GRUB2, then Linux... You should exercise exactly the same scenario as you described with Coreboot BSP. Then, you should take any and every possible detailed log which you can (to compare with the same scenario using Coreboot).
[B] You should see if you have the same behavior as you describe it in your original email.
[2] You say/write heading: USB EHCI power management. What about: USB xHCI power management (there is duality there, in Lynx Point PCH, don't you know?)?
I hope this email helps somehow. :-)
Zoran