Re: [PATCH] intel_idle: mention assumption that wbinvd is not needed

[Alexander Monakov]

On Mon, 12 Oct 2020, Rafael J. Wysocki wrote:

> > @@ -20,7 +20,11 @@
> >   * All CPUs have same idle states as boot CPU
> >   *
> >   * Chipset BM_STS (bus master status) bit is a NOP
> > - *     for preventing entry into deep C-stats
> > + *     for preventing entry into deep C-states
> > + *
> > + * CPU will flush caches as needed when entering a C-state via MWAIT
> 
> I would rephrase this to mention that the above actually is an assumption.

This comment block is by itself a list of assumptions. It begins with heading
"Design Assumptions" and then lists two assumptions. This patch adds a third
one.

With that clarified, do you still need me to change this hunk?

> 
> > + *     (in contrast to entering ACPI C3, where acpi_idle driver is
> 
> And mentioning acpi_idle here is not needed; it would be sufficient to
> say something like "in which case the WBINVD instruction needs to be
> executed to flush the caches".

I see, thanks, I will change this for v2 once the above is cleared up.

Thanks.
Alexander