powersaved is backwards on my machine...

powersaved is backwards on my machine...

[Erich Boleyn]

[just being clear, I am an AMD employee, though I am writing for
 myself at the moment]

Greetings,

Maybe this is a FAQ of some sort, but I couldn't find it with the
searches I tried, so I'm sending it here to know what the right thing
to do is...

I have an AMD machine which, when I enabled the powernow-k8 module and
powersaved, sets the power states opposite of what they should be.

I.e. when the machine is unloaded, it runs at the highest clock speed/
power state, and which the machine is loaded, it runs at the lowest
clock speed/power state.

I looked at the code a bit, and figured out the root causes:
  --  My old machine does not have correct ACPI power-state tables, so
	I disabled that.  (no, I can't get a BIOS update, sigh)
  --  It *does* have a functioning old Athlon64 PSB BIOS interface.
  --  powernow-k8 reports PSB-based power-states in ascending order
	instead of descending order like ACPI.
  --  powersaved assumes that the cpufreq interface will always
	report the power-states in descending order.

Fixing either cpufreq to report them always in descending order, or
powersaved to not assume it is in descending order is possebl...  but
the question is what the cpufreq interface *should* support.

So, I could not find any documentation on cpufreq that claimed the
frequency states listed should be in any particular order, but maybe
I was just not looking in the right place for the documentation...

--
    Erich Stefan Boleyn     <erich@uruk.org>     http://www.uruk.org/
"Reality is truly stranger than fiction; Probably why fiction is so popular"

Re: powersaved is backwards on my machine...

[Dominik Brodowski]

Hi,

On Mon, Aug 28, 2006 at 09:45:48AM -0700, Erich Boleyn wrote:
> So, I could not find any documentation on cpufreq that claimed the
> frequency states listed should be in any particular order, but maybe
> I was just not looking in the right place for the documentation...

There's no such documentation that I'm aware of :) and I don't see why we
should enforce any particular order here. So I'd say fixing powernowd is the
right approach here.

Thanks for debugging this!

	Dominik

Re: powersaved is backwards on my machine...

[Holger Macht]

On Mon 02. Oct - 19:18:48, Dominik Brodowski wrote:
> Hi,
> 
> On Mon, Aug 28, 2006 at 09:45:48AM -0700, Erich Boleyn wrote:
> > So, I could not find any documentation on cpufreq that claimed the
> > frequency states listed should be in any particular order, but maybe
> > I was just not looking in the right place for the documentation...
> 
> There's no such documentation that I'm aware of :) and I don't see why we
> should enforce any particular order here. So I'd say fixing powernowd is the
> right approach here.

Ok, so I will fix powersaved to sort the values after reading them from
scaling_avaialable_frequencies because I can't even assume that they are
in any particular order, neither descending nor ascending.

Regards,
	Holger

Re: powersaved is backwards on my machine...

[Erich Boleyn]

[-- Attachment #1: Type: text/plain, Size: 931 bytes --]

Holger Macht <hmacht@suse.de> wrote:

> On Mon 02. Oct - 19:18:48, Dominik Brodowski wrote:
> > Hi,
> > 
> > On Mon, Aug 28, 2006 at 09:45:48AM -0700, Erich Boleyn wrote:
> > > So, I could not find any documentation on cpufreq that claimed the
> > > frequency states listed should be in any particular order, but maybe
> > > I was just not looking in the right place for the documentation...
> > 
> > There's no such documentation that I'm aware of :) and I don't see why we
> > should enforce any particular order here. So I'd say fixing powernowd is the
> > right approach here.
> 
> Ok, so I will fix powersaved to sort the values after reading them from
> scaling_avaialable_frequencies because I can't even assume that they are
> in any particular order, neither descending nor ascending.

I had come to that conclusion as well, and made a tiny patch which did a
"qsort" on the values involved as a quick and dirty solution.


[-- Attachment #2: /home/erich/powersave-0.13.5-sort.patch --]
[-- Type: text/plain, Size: 789 bytes --]

diff -ruN powersave-0.13.5.orig/daemon/cpufreq_userspace.cpp powersave-0.13.5/daemon/cpufreq_userspace.cpp
--- powersave-0.13.5.orig/daemon/cpufreq_userspace.cpp	2006-08-14 03:57:16.000000000 -0700
+++ powersave-0.13.5/daemon/cpufreq_userspace.cpp	2006-08-29 21:54:02.000000000 -0700
@@ -24,6 +24,7 @@
 
 #include <sstream>
 #include <cpufreq.h>
+#include <stdlib.h>
 
 #include "cpufreq_interface.h"
 #include "globals.h"
@@ -328,6 +329,10 @@
 }
 #endif
 
+static int myqsortcmp(const void *a, const void *b)
+{
+	return (*(unsigned*)b) - (*(unsigned*)a);
+}
 
 int CPUFreq_Userspace::initFreqsViaFile()
 {
@@ -351,6 +356,9 @@
 		}
 	}
 
+	// Sort frequencies
+	qsort(&_speeds_kHz[0], speed_no, sizeof(unsigned), myqsortcmp);
+
 	_speeds_kHz[speed_no + 1] = 0;
 	_last_step = speed_no;
 

[-- Attachment #3: Type: text/plain, Size: 150 bytes --]

--
    Erich Stefan Boleyn     <erich@uruk.org>     http://www.uruk.org/
"Reality is truly stranger than fiction; Probably why fiction is so popular"

[-- Attachment #4: Type: text/plain, Size: 147 bytes --]

_______________________________________________
Cpufreq mailing list
Cpufreq@lists.linux.org.uk
http://lists.linux.org.uk/mailman/listinfo/cpufreq