Re: [PATCH v2 0/6] Improvements to PCI hibernate path

Bjorn Helgaas
2026-04-28T21:51:50Z

On Mon, Apr 27, 2026 at 03:50:18PM -0500, Mario Limonciello (AMD) wrote:
> A few cycles ago I sent out a kernel series for using the S4 paths when
> the system goes to S5. Some parts of it got merged, and Rafael suggested
> to split the other parts into smaller pieces across multiple kernel cycles
> to make bisecting easier.

Thanks for posting this again. Sashiko had a few questions:
https://sashiko.dev/#/patchset/20260427205024.254677-1-superm1%40kernel.org

I didn't look at them in detail, although I did think the ACPI r6.5
sec 16.1.5 reference was a little bit obscure. The diagram in sec
16.1 certainly implies that wakeups only occur in S1-S4 and not in S5.

Sec 16.1.5 does mention "Remote Start", which is completely undefined
by the spec but searching does find sec 7.4.2.6, which clearly says
the system requires a complete boot when awakened. Possibly a little
misleading to refer to Remote Start as "awakening" when it's
apparently not a "wakeup".

That section also says "OSPM does not disable wake events
before setting the SLP_EN bit when entering the S5 system state."