[coreboot] USB EHCI power management

Zoran Stojsavljevic zoran.stojsavljevic at gmail.com
Tue Dec 27 17:35:20 CET 2016

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
   [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. :-)


On Tue, Dec 27, 2016 at 10:24 AM, Аладышев Константин <aladyshev at nicevt.ru>

> I have a problem with USB EHCI on board with Lynxpoint-LP southbridge.
> First of all system doesn't wakeup from USB devices from S3. EHCI
> controller
> is listed in "/proc/acpi/wakeup" as "enabled" and GPE number is seemed to
> be
> configured correctly to PME_B0, but it doesn't work.
> More troubling issue that USB stops working after wakeup (for example from
> power button).
> In attempt to solve this issue I started to  investigate how exactly EHCI
> works in S3 suspend/resume sequence.
> And I have some questions:
> 1) PCI_config: PWR_CNTL_STS register (54-55h)
> What power state should enter EHCI controller when system enters S3?   D0
> state or D3hot ?
> 2) MEM_BASE: USB2.0_CMD (20-23h)
> Is it correct, that system disables "Run/Stop (RS)" bit when system enters
> S3?
> Is it correct, that all ports became suspended when system enters S3?
> 4) Who is responsible to set "Run/Stop (RS)" and bring USB ports from
> suspended state? BIOS or OS?
> 5) Is there any board in coreboot that has USB EHCI working correctly with
> S3 suspend/resume?
> --
> coreboot mailing list: coreboot at coreboot.org
> https://www.coreboot.org/mailman/listinfo/coreboot
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