[coreboot] Skylake ME power down mitigation timer

[Trammell Hudson]

Does anyone have experience with how long the Management Engine's
"Power Down Mitigation" timer is on Skylake? My Chell Chromebook
with modified ME firmware reports this on bootup / S3 resume:

ME: FW Partition Table : BAD
ME: Bringup Loader Failure : YES
ME: Firmware Init Complete : YES
ME: Manufacturing Mode : YES
ME: Boot Options Present : YES
ME: Update In Progress : YES
ME: D3 Support : YES
ME: D0i3 Support : YES
ME: Low Power State Enabled : YES
ME: Power Gated : YES
ME: CPU Replaced : YES
ME: CPU Replacement Valid : YES
ME: Current Working State : Unknown (15)
ME: Current Operation State : M0 without UMA but with error
ME: Current Operation Mode : M0 without UMA
ME: Error Code : Preboot
ME: Progress Phase : <NULL>
ME: Power Management Event : CM0PG->CM0
ME: Progress Phase State : Unknown phase: 0x0f state: 0xff
ME: Power Down Mitigation : YES
ME: PD Mitigation State : Issue Detected but not Recovered
ME: Encryption Key Override : Workaround Applied
ME: Encryption Key Check : FAIL
ME: PCH Configuration Info : Changed
ME: Firmware SKU : Unknown (0x7)

It's been up for almost two hours without shutting down.
The only drawback so far is that FSP takes quite a bit longer
to complete.

[Duncan Laurie]

I wouldn't read too much into the data in there, it turns out the ME
release that added this output detail (which we shipped in this device)
also got it wrong so the data is not reliable.

-duncan

Post by Trammell Hudson
Does anyone have experience with how long the Management Engine's
"Power Down Mitigation" timer is on Skylake? My Chell Chromebook
ME: FW Partition Table : BAD
ME: Bringup Loader Failure : YES
ME: Firmware Init Complete : YES
ME: Manufacturing Mode : YES
ME: Boot Options Present : YES
ME: Update In Progress : YES
ME: D3 Support : YES
ME: D0i3 Support : YES
ME: Low Power State Enabled : YES
ME: Power Gated : YES
ME: CPU Replaced : YES
ME: CPU Replacement Valid : YES
ME: Current Working State : Unknown (15)
ME: Current Operation State : M0 without UMA but with error
ME: Current Operation Mode : M0 without UMA
ME: Error Code : Preboot
ME: Progress Phase : <NULL>
ME: Power Management Event : CM0PG->CM0
ME: Progress Phase State : Unknown phase: 0x0f state: 0xff
ME: Power Down Mitigation : YES
ME: PD Mitigation State : Issue Detected but not Recovered
ME: Encryption Key Override : Workaround Applied
ME: Encryption Key Check : FAIL
ME: PCH Configuration Info : Changed
ME: Firmware SKU : Unknown (0x7)
It's been up for almost two hours without shutting down.
The only drawback so far is that FSP takes quite a bit longer
to complete.
--
Trammell
--
https://www.coreboot.org/mailman/listinfo/coreboot

[Trammell Hudson]

Post by Duncan Laurie
I wouldn't read too much into the data in there, it turns out the ME
release that added this output detail (which we shipped in this device)
also got it wrong so the data is not reliable.

Interesting. Do you mean the ME firmware release that was installed
in the boot ROM? Has Intel shipped an updated firmware file for the
platform?

Post by Duncan Laurie

Post by Trammell Hudson
The only drawback so far is that FSP takes quite a bit longer
to complete.

I should say "FSPMemoryInit" takes longer; "FSPTempRamInit" is still
as fast as before.

I've removed all of the code from the ME firmware image, except the rbe,
kernel, syslib and bup files. I've also resized the ME region from
0x1000-0x1FFFFF to 0x1000-0xFFFFF. This potentially makes another 1 MB
available to the coreboot payload.

Post by Duncan Laurie

Post by Trammell Hudson
It's been up for almost two hours without shutting down.

The system has been functional most of the day, so the 30 minute
timer does not seem to be active on this platform. Everything seems
to work fine: S3 suspend/resume is slow, but does the right thing now,
and powertop says the system is around 5W idle (Qubes with a 4.4 kernel,
mjg59 mentioned that kernel can't take advantage of low power states).

[Duncan Laurie]

Post by Trammell Hudson

Post by Duncan Laurie
I wouldn't read too much into the data in there, it turns out the ME
release that added this output detail (which we shipped in this device)
also got it wrong so the data is not reliable.

Interesting. Do you mean the ME firmware release that was installed
in the boot ROM? Has Intel shipped an updated firmware file for the
platform?

The power down mitigation thing you see is related to an errata and not
part of the usual watchdog timers. I turn off the AMT watchdog timer in
our images so hopefully you will not see a problem there.

Intel makes new ME releases for all current and legacy platforms on a
pretty regular basis, but we don't update unless there is a good reason.

Post by Trammell Hudson

Post by Duncan Laurie

Post by Trammell Hudson
The only drawback so far is that FSP takes quite a bit longer
to complete.

I should say "FSPMemoryInit" takes longer; "FSPTempRamInit" is still
as fast as before.
I've removed all of the code from the ME firmware image, except the rbe,
kernel, syslib and bup files. I've also resized the ME region from
0x1000-0x1FFFFF to 0x1000-0xFFFFF. This potentially makes another 1 MB
available to the coreboot payload.

I suspect the longer time spent in FspMemoryInit is due to FSP attempting
to send HECI messages to the ME and timing out.

It looks like Kabylake FSP 2.0 exposes an option for HeciTimeouts which
could be set to 0 to disable the timeouts. But that is not part of the
Skylake FSP 1.1, so you won't be able to take advantage of it quite yet.
Once we're done with Kabylake integration and the Kabylake FSP 2.0 is
released that may be an option.

Post by Trammell Hudson

Post by Duncan Laurie

Post by Trammell Hudson
It's been up for almost two hours without shutting down.

The system has been functional most of the day, so the 30 minute
timer does not seem to be active on this platform. Everything seems
to work fine: S3 suspend/resume is slow, but does the right thing now,
and powertop says the system is around 5W idle (Qubes with a 4.4 kernel,
mjg59 mentioned that kernel can't take advantage of low power states).

Ya without ME firmware you're not going to get very low idle numbers since
it is involved in a lot of power management and clock gating. But the fact
that it works at all is progress...

-duncan