On 3.01.2025 8:28 AM, Christoph Hellwig wrote: > On Fri, Dec 20, 2024 at 04:15:21PM +0100, Konrad Dybcio wrote: >> The Qualcomm platform (or class of platforms) we're looking at with this >> specific issue requires PCIe (implying NVMe) shutdown for S2RAM. >> >> The S2RAM entry mechanism is unfortunately misrepresented as an S2Idle >> state by Linux as of today, and I'm trying really hard to convince some >> folks to let me describe it correctly, with little success so far.. > > Well, not advertizing the right mechanism isn't going to cause havoc > to any scheme. > >> That is the real underlying issue and once/if it's solved, this patch >> will not be necessary. > > Well, maybe this thread gave good enough fodder to finally fix it? Oh I'd love to.. But my changes are getting rejected over philosophical FW design disagreements, it seems. Konrad > >> >>> In theory, ACPI S3 or hibernation may request that, but I've never >>> seen it happen in practice. >>> >>> Suspend-to-idle on x86 may want devices to end up in specific power >>> states in order to be able to switch the entire platform into a deep >>> energy-saving mode, but that's never been D3cold so far. >> >> In our case the plug is only pulled in S2RAM, otherwise the best we can >> do is just turn off the devices individually to decrease the overall >> power draw > > FYI, going to D3 for S2RAM seems perfectly reasonable from the NVMe POV. >
