Re: cpufreq est and Enhanced Sleep (Cx) States for Intel Core and above

Adam McDougall wrote:
> On Wed, Dec 13, 2006 at 12:14:55PM -0500, Stephane E. Potvin wrote:
> 
>   Adam McDougall wrote:
>   >On Sat, Dec 09, 2006 at 07:29:23PM -0500, Adam McDougall wrote:
>   >
>   >  Another thing I wish could work is the Enhanced cpu Sleep States;
>   >  this Dell Latitude D820 laptop only sees C1 although the document
>   >  above indicates it should probably support 4 unique states.  Is 
>   >  there a way I can debug and/or fix this?  I can post dumps of the
>   >  acpi stuff and/or verbose boot logs if it would be helpful.  
>   >  
>   >  Thanks
>   >  _______________________________________________
>   >
>   >I am attaching my asl and dsdt acpi dumps incase someone knows for
>   >something to look for as for why it thinks I only have C1, unless 
>   >its related to the speed control problem above.  
>   >
>   Hi Adam,
>   
>   It's only finding the C1 state for various reasons that you'll find 
>   described in some details in the following email that I send to the acpi 
>   mailing list in June this year. The major reason being that the acpi cpu 
>   driver does not support well multiprocessor systems.
>   
>   http://docs.freebsd.org/cgi/getmsg.cgi?fetch=116103+0+archive/2006/freebsd-acpi/20060611.freebsd-acpi
>   
>   The email also included a patch to add support for multiprocessor 
>   systems to the acpi cpu driver. I've not updated the patch since then so 
>   it might or might not apply cleanly to a recent current.
>   
>   Steph
> 
> I didn't get around to trying that patch, but I have tried -current 
> after code was committed, including as late as Feb 11.  It seems to work,
> but if both of my cpus are allowed to enter C3 state, my laptop
> clock stops advancing (unless you are causing activity) and the performance
> gets very choppy, including mouse cursor halting for a second or two, etc.
> Typing or moving the mouse seems to nudge the system into crawling along,
> but if I leave it alone, timing loops stall.  I could do a while loop with
> a sleep on the command line and time just doesn't advance on its own, and
> the clock in Gnome would halt.  My laptop is using the Hpet timer, but it
> doesn't seem to make a difference if I use sysctl to try ACPI-fast or i8254.
>


Could you try the attached patch on your system? It adds a crude check
to make sure that the system is not sleeping for more than 1/hz secs.
The acpi_cpu driver should back off to a lower Cx state if it does.

Steph