[coreboot] T530: Cleaning Intel ME currently does not work <--> CPU fan won't start

[Nico Huber]

Hi,

On 20.07.2017 23:48, Pavel Alyev wrote:
> 
> Not at all. ME can control clock output frequency at GPIO 64/65/66/67.
> From coreboot you can only set these pins to NATIVE mode. So, if you
> EC/SIO take clock input from PCH, without ME they may work incorrectly.

you are right. I forgot that the ThinkPad EC is more a Super-I/O and may
need the PCH to work (and not the other way around). And it's indeed
connected to SUSCLK (GPIO62). Although I don't know what it does with
that clock, it's possible that the ME messes with it.

> 
> But looks like at t530 this outputs sets in GPIO mode. David, can you
> dump gpios from system with running ME (can be done by 'inteltool -g').

GPIO62 is set to native mode.

Nico

> 
> 
> 20.07.2017 20:58, Nico Huber пишет:
>> Hi David,
>>
>> On 20.07.2017 18:44, David Hobach wrote:
>>> Dear all,
>>>
>>> just tested two coreboot + SeaBios images on a T530 that were identical
>>> except one time with ME and one time without (using the compile option,
>>> rev 54db255529ce8afc689ae425c24b7fb1d45654e8).
>>>
>>> Unfortunately it seems that ME does some CPU fan initialization (ACPI?)
>>> that coreboot doesn't, i.e. on the image without ME the CPU fan didn't
>>> start anymore = not usable. I tested with Fedora 26 and ubuntu 14.02 LTS
>>> up to temperatures of 98 degrees celsius, but it wouldn't start. I
>>> didn't test manual fan control.
>> the fan should be controlled by the EC which runs independently of the
>> ME and the host CPU. There are some settings the host CPU can write into
>> the EC RAM (coreboot should do that, the ME doesn't know anything about
>> it). It might be that coreboot does something wrong (e.g. trying to ap-
>> ply these settings while the EC is not ready yet after the reset) and
>> that it only becomes obvious after the EC has been reset (and even then
>> it would depend on the EC firmware, so YMMV). Another explanation could
>> be that something broke during the flashing (not due to bad data in the
>> flash but due to an overall bad state of the hardware). In which way did
>> you flash? did you use the internal flasher? an external one? if exter-
>> nal, did you connect an external power supply to the flash chip? All
>> bets are off, if you did the the latter.
>>
>> Though unlikely, the following could also be the case: with the cleaned
>> ME the system is in a weird state where it can't correctly write the EC
>> RAM registers. But I really doubt that if the host behaves well other-
>> wise.
>>
>> In any case, I'd check the coreboot log for errors.
>>
>> Nico
>>
>