Updated acpi_cpu patch

Lukas Ertl l.ertl at univie.ac.at
Tue Nov 18 13:37:30 PST 2003

On Tue, 18 Nov 2003, Nate Lawson wrote:

> On Tue, 18 Nov 2003, Lukas Ertl wrote:
> > hw.acpi.cpu.cx_supported: C1/1 C2/1 C3/85
> > hw.acpi.cpu.cx_lowest: 0
> > hw.acpi.cpu.cx_history: 86231/0 0/0 0/0
> Try settings of cx_lowest of 1 and 2 (and 3 when the last C3 state is
> available).  I'm interested in any benchmark results, especially IO.  I'm
> hoping the scheduling of sleeps is good enough that you don't experience
> much performance loss even with lower sleeps.

I'm gonna try some "buildkernelstones" with the different settings.  If
you have some special benchmarks in mind I'd be happy to run them.

> > Although it seems I have lost a C3 state (before, I had an additional
> > C3/185).
> _CST can change dynamically at runtime.  If you booted with the AC adapter
> attached, your laptop may not offer all the sleep states.  When you unplug
> the AC adapter, we get a notify on _CST to re-evaluate it and look for new
> states.  However, that code is currently disabled due to complex locking
> issues (i.e. what to do when a Cx state is being accessed but _CST is
> being re-evaluated).  _CST re-evaluation won't be enabled until after
> 5.2R.  However, you can reboot your laptop with the AC adapter detached
> (or attached) to see what states are available.

Ah, yes, that would explain it - I just booted on battery.

> This excerpt from truckman@'s asl shows that 4 Cx states are only
> available when the AC adapter is not attached.  (The C*NA memory addresses
> appear to be managed by the BIOS and not the AML but the PSR access is
> clear).

This part of the ASL looks the one here - let me guess, is it a ThinkPad?


Lukas Ertl                             eMail: l.ertl at univie.ac.at
UNIX Systemadministrator               Tel.:  (+43 1) 4277-14073
Vienna University Computer Center      Fax.:  (+43 1) 4277-9140
University of Vienna                   http://mailbox.univie.ac.at/~le/

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