[coreboot] Asus KGPE-D16 non-working S3 suspend with Qubes 4

[Timothy Pearson]

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On 12/10/2018 01:55 PM, Angel Pons wrote:
> Hello,
> 
> On Mon, Dec 10, 2018, 19:45 Taiidan at gmx.com <mailto:Taiidan at gmx.com>
> <Taiidan at gmx.com <mailto:Taiidan at gmx.com> wrote:
> 
>     S3 - it does work but you just have to wait a long time I would guess
>     that maybe there is some ram re-training going on and that is why
>     resuming from S3 takes over a minute.
> 
> 
> AFAIK, retraining the RAM destroys its contents (and that is why timings
> must be cached to flash for S3 to work). Does AMD have anything special
> to retrain memory yet still preserve RAM data to allow suspend, or am I
> missing something here?
> 
> Best regards,
> 
> Angel Pons
> 

You are correct.  The memory is not (and cannot be) retrained, the
previous settings are loaded from the s3nv region of Flash (this is also
why the settings change on each boot -- the last known good training
data is loaded into Flash to support resume from suspend).

My understanding is that because the current coreboot native AMD
codebase doesn't support relocatable ramstage (yet?) we're hitting a
slow path somewhere in resume.  I think there was some work being put
into adding the relocateable ramstage support but I don't know current
status.

- -- 
Timothy Pearson
Raptor Engineering
+1 (415) 727-8645 (direct line)
+1 (512) 690-0200 (switchboard)
https://www.raptorengineering.com
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