Re: glymur: hard reset on the first system-domain idle entry (SS3, 0x0200c354) after a heavy load - Lenovo Yoga Slim 7x Gen 11

[Oleg Keri]

Hi Joonhoe,

Thanks, that is useful. On Glymur (Lenovo Yoga Slim 7x Gen 11) the
pattern is different:

- Plain idle has never reset here: 50,000+ cluster (0x01000054) entries
  and hundreds of SS3 entries without a reset.
- The reset needs a trigger: the first SS3 entry right after a full
  all-core load (a kernel build or stress), 5 out of 5.
- With SS3 removed from the system domain and the cluster state kept,
  3 out of 3 runs of that trigger survived.
- Day to day I run with a cpu_dma_latency constraint of 1500 us, which
  vetoes both the cluster state and SS3 at runtime, and I have not seen
  a runtime reset with it in place.

Glymur has a single CPU idle state, 0x4 retention, which is also the CPU
domain state, so every cluster entry here has its CPUs in retention. I
cannot separate the two the way you did.

A correction to my original report: the min-residency override did not
hold. With no timer pending on any CPU the governor's idle estimate is
effectively unbounded, so the residency check passes, and I had a reset
with it in place. Only removing SS3 from the system domain survived.

Oleg