On Sun, 2007-04-29 at 17:24 +0200, Mikael Pettersson wrote:
> On Thu, 26 Apr 2007 15:42:44 -0700, john stultz wrote:
> >Another shot in the dark:
> >
> >I wonder if the ACPI PM counter is halting in idle. Does booting w/
> >idle=poll change the behavior? (Please do this while your laptop is
> >plugged in, as it will run the cpu at full speed all the time).
>
> Bingo!
Awesome! Finally, some progress! Thanks again for putting up w/ all my
testing requests.
> I booted the x86-64 2.6.21 final kernel with idle=poll and let the
> laptop idle for an hour. The ondemand cpufreq governor did reduce
> the CPU's clock frequency, but that shouldn't have affected the
> chipset or the ACPI PM counter.
>
> Anyway, after 60 minutes `date' and `hwclock' were still in perfect
> sync and matched actual time.
>
> Any ideas why this halting in idle doesn't happen with the 32-bit kernel?
No clue. Time to ask Len. :)
Hey Len,
So that slow acpi_pm on x86_64 seems to be connected w/ the idle loop.
I'm guessing the chipset halts the ACPI PM in lower C states. Do you
have any guesses as to what might differ between x86_64 and i386 ACPI
idle loops? Or might this be something different in what the BIOS
exports in x86_64 mode or i386 mode?
Any suggestions on how to dig through this?
Thomas: Heads up, the ACPI PM might be flakier then we thought.
thanks
-john
On Wed, 2007-05-02 at 11:10 -0700, john stultz wrote:
> On Sun, 2007-04-29 at 17:24 +0200, Mikael Pettersson wrote:
> > On Thu, 26 Apr 2007 15:42:44 -0700, john stultz wrote:
> > >Another shot in the dark:
> > >
> > >I wonder if the ACPI PM counter is halting in idle. Does booting w/
> > >idle=poll change the behavior? (Please do this while your laptop is
> > >plugged in, as it will run the cpu at full speed all the time).
> >
> > Bingo!
>
> Awesome! Finally, some progress! Thanks again for putting up w/ all my
> testing requests.
>
> > I booted the x86-64 2.6.21 final kernel with idle=poll and let the
> > laptop idle for an hour. The ondemand cpufreq governor did reduce
> > the CPU's clock frequency, but that shouldn't have affected the
> > chipset or the ACPI PM counter.
> >
> > Anyway, after 60 minutes `date' and `hwclock' were still in perfect
> > sync and matched actual time.
> >
> > Any ideas why this halting in idle doesn't happen with the 32-bit kernel?
>
> No clue. Time to ask Len. :)
>
> Hey Len,
> So that slow acpi_pm on x86_64 seems to be connected w/ the idle loop.
> I'm guessing the chipset halts the ACPI PM in lower C states. Do you
> have any guesses as to what might differ between x86_64 and i386 ACPI
> idle loops? Or might this be something different in what the BIOS
> exports in x86_64 mode or i386 mode?
Mikael,
Just trying to dig a bit more through the acpi_processor_idle code.
Could you run "cat /proc/acpi/processor/CPU1/power" and reply w/ the
output?
thanks
-john