[coreboot] GM45 S3 resume issues

[Nico Huber]

On 12.11.2015 04:37, Patrick 'P. J.' McDermott wrote:
> On 2015-11-11 16:50, Nico Huber wrote:
>> Hi,
>>
>> On 11.11.2015 00:49, Patrick 'P. J.' McDermott wrote:
>>> I've been looking into S3 resume on GM45 mainboards, which often fails
>>> in rather interesting ways.
>> Well, the S3 support wasn't really tested during GM45 development. Maybe
>> it's just plainly broken. My development system at work (roda/rk9)
>> doesn't resume because of another problem (but didn't fail raminit on
>> the resume path in 3 of 3 tries). So it will need some work before I can
>> test this.
> 
> Ah, OK.  What kind of other problem?  In addition to the raminit reset,
> I've seen resume fail by an SMM hang and in other ways.
There was a minor flaw in the mainboard code:
  http://review.coreboot.org/#/q/topic:rk9-resume
With patches applied, it works halfway reliable: about 30 good suspend-
resume cycles before it fails. Only eye-catching thing in dmesg was a
warning about the backlight being already enabled. I haven't yet a
serial log for a failed resume.

One more thing that came in mind: The reset after a failed receive-
enable calibration is kind of wanted. IIRC, we left the watchdog enable
for a case of failing raminit. But I don't remember what the exact fai-
lure was. It wasn't very unlikely to occur (> 1/1000). If we run into
this on the resume path too, it might never work reliable :-/

Nico