[coreboot] GM45 S3 resume issues

Patrick 'P. J.' McDermott pj at pehjota.net
Thu Nov 12 23:16:27 CET 2015

[Resending after accidentally replying off-list]

On 2015-11-12 14:32, Nico Huber wrote:
> 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

Ah, I see.  Yeah, X200 and T400 romstages don't have that flaw.

> 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.

How does it fail?

> 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 :-/

Patrick "P. J." McDermott
Lead Developer, ProteanOS

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