[coreboot] [RFH] Native AMD fam10-15 support

[Kyösti Mälkki]

On Fri, Jul 13, 2018 at 6:44 AM, Timothy Pearson <
tpearson at raptorengineering.com> wrote:

> On 07/12/2018 10:41 PM, Kyösti Mälkki wrote:
> > On Fri, Jul 13, 2018 at 5:41 AM, Timothy Pearson
> > <tpearson at raptorengineering.com <mailto:tpearson at raptorengineering.com>>
> > wrote:
> >
> >     Good to know, thanks for testing!  I've been looking into
> relocateable
> >     ramstage in case suspend was still failing, but if things fell back
> into
> >     place, so to speak, in master we should also look at reactivating
> REACTS
> >     with the suspend tests enabled.
> >
> >
> > I never suspected RELOCATABLE_RAMSTAGE=n would be a reason for
> > (possible) S3 regressions. The motivation for having
> > RELOCATABLE_RAMSTAGE=y goes beyond the improvement it has on not having
> > to do low-mem backup S3 resume path. I am also wondering how S3 resume
> > path is taking one minute and how that relates to normal boot path time.
> >
> > Kyösti
>
> My understanding is that without relocateable ramstage, there are
> additional bounce buffers involved that not only slow things down, but
> also introduce new code paths that could be responsible for regressions
> in resume.  I think avph on IRC is looking into an initial port of the
> CAR code for relocateable support, and if things are stable enough in
> master to reactivate the REACTS tests on the KGPE-D16 that would help
> him iterate more quickly.
>
>
Right, with RELOCATABLE_RAMSTAGE=n there is a back-and-forth of low-memory
region ramstage occupies on S3 resume path. Also you do not have benefit of
executing a copy of ramstage that was cached in RAM already on normal boot
path, but have to decompress it again from flash.

The low-memory copy is not that big, RAMBASE..RAMTOP is 3 MiB, so this does
not explain one minute.

Indeed RELOCATABLE_RAMSTAGE=n is already in the minority now and
bounce-buffer logic recently had some regressions for loading some payloads.

Kyösti
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