2005-09-01 18:45:35

by Brown, Len

[permalink] [raw]
Subject: RE: [PATCH] acpi-cpufreq: Remove P-state read after a P-state write in normal path

>How can we handle it, if we do not even know that it failed?
>How should the user recognize something is broken?

We probably shouldn't have used the word "fail" here.

I expect the IO and MSR accesses will always "succeed",
but they may not always have the exact effect the OS requested.
I think we (the OS) need to get used to this.

The HW reserves the right to second guess the OS for a
variety of reasons, including temperature, power,
reliability, or dependencies between different hardware
units that may not be exposed to the OS. I think as
hardware becomes more complex and more power-optimized,
we'll see more of this, not less.

cheers,
-Len