Mika Westerberg writes:
> The problem here is that the S3 path which may accidentally work may
> break something else because it was never tested by Lenovo.
No, that isn't what Lenovo says. The BIOS documentation for this laptop
even mentions S3. What Lenovo says is that they kicked S3 out of DSDT to
work around a Windows bug. ("Dear customers, When ACPI table was changed
to support S3, Windows Modern Standby doesn't work. Modern Standby and
Suspend/Resume functions are working exclusively.")
The links also show Linux users consistently being happier with this
laptop after enabling S3 through a DSDT override. There are also enough
tests to confidently say that this kernel patch also enables S3 on this
laptop, without a DSDT override.
The concerns I was expressing about testing come from the possibility
that the patch accidentally affects _other_ laptops---that I might have
screwed up something in the DMI part or the setup part.
> One thing that consumes quite lot power are the two Thunderbolt ports on
> that system. They are always present (unless you go and switch to legacy
> Thunderbolt mode from the BIOS)
This is only part of the problem. The links that I provided show tons of
complaints about Linux s2idle power consumption on this laptop _after_
people turn on Thunderbolt assist in the BIOS. Note that we're talking
about a flagship Lenovo laptop here, not something obscure.
Also, do you have any idea why Linux s2idle doesn't wake up on this
laptop under Xen? For me, adding S3 support made the difference between
* a laptop that I'm using with Linux every day and
* a useless un-suspendable laptop.
Evidently there's still interesting work to do on Linux s2idle even
after years of development. Perhaps enough s2idle development will
remove the need for S3 on this laptop. However, I don't see a schedule
for making this happen. The current situation is that the S3 patch is
working and s2idle isn't.
---Dan
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