Re: 2.6.17 -> 2.6.18 regression: cpufreq broken since 2.6.18-rc1 on pentium4

Re: 2.6.17 -> 2.6.18 regression: cpufreq broken since 2.6.18-rc1 on pentium4

[bert hubert]

>   I have similar problem with cpufreq-nforce2 -- http://lkml.org/lkml/2006/7/7/234
>   I haven't do a git-bisect yet.

To recap, cpufreq died for at least two people (Tomasz Torcz and me) between
2.6.17 and 2.6.18-rc1. I've cc'd everybody who touched cpufreq according to
the shortlog.

Abundant details are in:

http://lkml.org/lkml/2006/7/30/87

New information is that I've narrowed it down from between 2.6.16.9 and
2.6.18-rc1 to between 2.6.17.7 (which works) and 2.6.18-rc1 (which doesn't).

The problem exists both with cpufreq as modules and staticly, and both with
P4 and nforce2.

Please let me know how I can help you solve this problem. I'll try a git
bisect but a lot of the cpufreq changes appear to be interrelated, so I'm
unsure if it will work.

Thanks!

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Re: 2.6.17 -> 2.6.18 regression: cpufreq broken since 2.6.18-rc1 on pentium4

[Alexey Starikovskiy]

Do I understand your logs right and acpi-cpufreq is already loaded and works on your processor?
Do you have any info in /sys/devices/system/cpu/cpu0/cpufreq ?
Why do you want to load p4-clockmod over it? It does not save you any power, just limits performance.

Regards,
	Alex.

bert hubert wrote:
>>   I have similar problem with cpufreq-nforce2 -- http://lkml.org/lkml/2006/7/7/234
>>   I haven't do a git-bisect yet.
> 
> To recap, cpufreq died for at least two people (Tomasz Torcz and me) between
> 2.6.17 and 2.6.18-rc1. I've cc'd everybody who touched cpufreq according to
> the shortlog.
> 
> Abundant details are in:
> 
> http://lkml.org/lkml/2006/7/30/87
> 
> New information is that I've narrowed it down from between 2.6.16.9 and
> 2.6.18-rc1 to between 2.6.17.7 (which works) and 2.6.18-rc1 (which doesn't).
> 
> The problem exists both with cpufreq as modules and staticly, and both with
> P4 and nforce2.
> 
> Please let me know how I can help you solve this problem. I'll try a git
> bisect but a lot of the cpufreq changes appear to be interrelated, so I'm
> unsure if it will work.
> 
> Thanks!
> 

Re: 2.6.17 -> 2.6.18 regression: cpufreq broken since 2.6.18-rc1 on pentium4

[bert hubert]

On Sun, Jul 30, 2006 at 10:07:18PM +0400, Alexey Starikovskiy wrote:
> Do I understand your logs right and acpi-cpufreq is already loaded and 
> works on your processor?

Yes, I can load it, but I'm unable to figure out what it is supposed to do,
or if it is doing anything.

> Do you have any info in /sys/devices/system/cpu/cpu0/cpufreq ?

No, not with just acpi-cpufreq loaded. With the help of Zwane, I've
discovered that if I unload acpi-cpufreq, I *can* load p4-clockmod, and then
the directory you mention appears, and I can configure governors, and life
is good. This all on 2.6.18-rc3.

Do I understand correctly that acpi-cpufreq is supposed to offer comparable
features?

Perhaps acpi-cpufreq *has* loaded, but did not find the proper hooks, but
has now registered itself, thus blocking p4-clockmod? When everything is
in-kernel, acpi-cpufreq might register itself first, which would lead to the
same thing.

For completeness, lspci. This is a desktop system, but I need some kind of
governer for quiet running.

$ lspci
0000:00:00.0 Host bridge: Intel Corporation 915G/P/GV/GL/PL/910GL Processor to I/O Controller (rev 04)
0000:00:01.0 PCI bridge: Intel Corporation 915G/P/GV/GL/PL/910GL PCI Express Root Port (rev 04)
0000:00:02.0 VGA compatible controller: Intel Corporation 82915G/GV/910GL Express Chipset Family Graphics Controller (rev 04)
0000:00:1b.0 0403: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) High Definition Audio Controller (rev 03)
0000:00:1c.0 PCI bridge: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) PCI Express Port 1 (rev 03)
0000:00:1c.1 PCI bridge: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) PCI Express Port 2 (rev 03)
0000:00:1c.2 PCI bridge: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) PCI Express Port 3 (rev 03)
0000:00:1c.3 PCI bridge: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) PCI Express Port 4 (rev 03)
0000:00:1d.0 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #1 (rev 03)
0000:00:1d.1 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #2 (rev 03)
0000:00:1d.2 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #3 (rev 03)
0000:00:1d.3 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #4 (rev 03)
0000:00:1d.7 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB2 EHCI Controller (rev 03)
0000:00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev d3)
0000:00:1f.0 ISA bridge: Intel Corporation 82801FB/FR (ICH6/ICH6R) LPC Interface Bridge (rev 03)
0000:00:1f.1 IDE interface: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) IDE Controller (rev 03)
0000:00:1f.2 IDE interface: Intel Corporation 82801FB/FW (ICH6/ICH6W) SATA Controller (rev 03)0000:00:1f.3 SMBus: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) SMBus Controller (rev 03)
0000:06:00.0 Network controller: Techsan Electronics Co Ltd B2C2 FlexCopII DVB chip / Technisat SkyStar2 DVB card (rev 02)
0000:06:08.0 Ethernet controller: Intel Corporation 82562ET/EZ/GT/GZ - PRO/100 VE (LOM) Ethernet Controller (rev 01)

Thanks!

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Re: 2.6.17 -> 2.6.18 regression: cpufreq broken since 2.6.18-rc1 on pentium4

[Dave Jones]

On Sun, Jul 30, 2006 at 08:44:43PM +0200, bert hubert wrote:
 
 > > Do you have any info in /sys/devices/system/cpu/cpu0/cpufreq ?
 > 
 > No, not with just acpi-cpufreq loaded. With the help of Zwane, I've
 > discovered that if I unload acpi-cpufreq, I *can* load p4-clockmod, and then
 > the directory you mention appears, and I can configure governors, and life
 > is good. This all on 2.6.18-rc3.

Right, cpufreq drivers aren't 'stackable'.

 > Do I understand correctly that acpi-cpufreq is supposed to offer comparable
 > features?

If the BIOS supports the relevant ACPI tables.

 > Perhaps acpi-cpufreq *has* loaded, but did not find the proper hooks, but
 > has now registered itself, thus blocking p4-clockmod? When everything is
 > in-kernel, acpi-cpufreq might register itself first, which would lead to the
 > same thing.

Normally, if the necessary BIOS bits aren't there, then acpi-cpufreq will
fail to register.  For some reason it sounds like it believes that everything
went ok.  I wonder if something changed in acpi recently that caused this
change in behaviour ? Len ?

		Dave

-- 
http://www.codemonkey.org.uk

Re: 2.6.17 -> 2.6.18 regression: cpufreq broken since 2.6.18-rc1 on pentium4

[bert hubert]

On Sun, Jul 30, 2006 at 03:01:33PM -0400, Dave Jones wrote:

> Normally, if the necessary BIOS bits aren't there, then acpi-cpufreq will
> fail to register.  For some reason it sounds like it believes that everything
> went ok.  I wonder if something changed in acpi recently that caused this
> change in behaviour ? Len ?

As far as I can see, acpi_cpufreq does not pass on any errors it sees during
init:

static int __init acpi_cpufreq_init (void)
{
        int                     result = 0;

        dprintk("acpi_cpufreq_init\n");

        result = acpi_cpufreq_early_init_acpi();
...

And from acpi_cpufreq_early_init_acpi():

static int acpi_cpufreq_early_init_acpi(void)
{
        struct acpi_processor_performance       *data;
        unsigned int                            i, j;

        dprintk("acpi_cpufreq_early_init\n");

	( some memory allocations, does not look at acpi or bios )
	
        /* Do initialization in ACPI core */
        acpi_processor_preregister_performance(acpi_perf_data);
        return 0;
}

Note how any error from acpi_processor_preregister_performance is ignored.

Ghetto patch which "fixes" the problem for me:

--- ./arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c~orig  2006-07-30 21:14:43.000000000 +0200
+++ ./arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c       2006-07-30 21:11:34.000000000 +0200
@@ -384,8 +384,7 @@
        }

        /* Do initialization in ACPI core */
-       acpi_processor_preregister_performance(acpi_perf_data);
-       return 0;
+       return acpi_processor_preregister_performance(acpi_perf_data);
 }


But tonight I have no speedstep laptop available to check if this does not
kill acpi_cpufreq when it can work.

Thanks for the hint, dave!

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Re: 2.6.17 -> 2.6.18 regression: cpufreq broken since 2.6.18-rc1 on pentium4

[bert hubert]

> went ok.  I wonder if something changed in acpi recently that caused this
> change in behaviour ? Len ?

Dave,

I'm no expert but I think it was you that made this change in
http://kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blobdiff;h=567b39bea07e4fbbe091b265b010905e3d30ff5a;hp=1a7bdcef19261deff5a7ea8ee13d5a8ddb434a19;hb=911cb74bb9e77e40749abc2fca6fe74d87d940f3;f=arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c

+ /* Do initialization in ACPI core */
+ acpi_processor_preregister_performance(acpi_perf_data);
+ return 0;
+}

:-)

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Re: 2.6.17 -> 2.6.18 regression: cpufreq broken since 2.6.18-rc1 on pentium4

[Dave Jones]

On Mon, Jul 31, 2006 at 09:08:01AM +0200, bert hubert wrote:
 > > went ok.  I wonder if something changed in acpi recently that caused this
 > > change in behaviour ? Len ?
 > 
 > Dave,
 > 
 > I'm no expert but I think it was you that made this change in
 > http://kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blobdiff;h=567b39bea07e4fbbe091b265b010905e3d30ff5a;hp=1a7bdcef19261deff5a7ea8ee13d5a8ddb434a19;hb=911cb74bb9e77e40749abc2fca6fe74d87d940f3;f=arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c
 > 
 > + /* Do initialization in ACPI core */
 > + acpi_processor_preregister_performance(acpi_perf_data);
 > + return 0;
 > +}
 > 
 > :-)

I'm puzzled. As that commit message doesn't match the diff.
If you click "commitdiff", you'll see the actual commit for that msg,
which is a one-liner.

Your change in your previous mail makes sense to me though,
so I'll commit it to cpufreq.git later today.

		Dave


-- 
http://www.codemonkey.org.uk

Re: 2.6.17 -> 2.6.18 regression: cpufreq broken since 2.6.18-rc1 on pentium4

[bert hubert]

On Mon, Jul 31, 2006 at 12:20:46PM -0400, Dave Jones wrote:

> Your change in your previous mail makes sense to me though,
> so I'll commit it to cpufreq.git later today.

Do you think this will make 2.6.18? Otherwise any kernel with acpi_list
compiled in will have no frequency scaling, unless it supports scaling over
ACPI.

Thanks!

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Re: 2.6.17 -> 2.6.18 regression: cpufreq broken since 2.6.18-rc1 on pentium4

[Dave Jones]

On Mon, Jul 31, 2006 at 08:57:13PM +0200, bert hubert wrote:
 > On Mon, Jul 31, 2006 at 12:20:46PM -0400, Dave Jones wrote:
 > 
 > > Your change in your previous mail makes sense to me though,
 > > so I'll commit it to cpufreq.git later today.
 > 
 > Do you think this will make 2.6.18? Otherwise any kernel with acpi_list
 > compiled in will have no frequency scaling, unless it supports scaling over
 > ACPI.

Yes, I'll queue it for .18

		Dave

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