On Wednesday 27 August 2008 19:03:52 Dave Jones wrote:
> On Wed, Aug 27, 2008 at 05:44:01PM +0200, Thomas Renninger wrote:
> > I posted this on acpi list first.
> > Andi had concerns about what the best way would be to get
> > this merged as two subsystems are touched:
> > --------
> > Looks good to me now. The only issue is that the patchkit is cross
> > subsystem (cpufreq and ACPI). Either the patches go in through Andrew or
> > we need to figure out how to merge this.
>
> I really couldn't care less about how this gets merged.
> It all seems rather pointless to me.
?!?
The message "MP tables not supported" (or similar) on AMD machines
is rather common.
On Intel CPUs the same problem more seems to be exposed by a _PPC
(an ACPI cpufreq related function), but missing _PSS frequency tables.
Both have the same cause: The CPU is newer than the BIOS and thus
the BIOS cannot fill the ACPI table with valid CPU frequency information.
I thought especially the two CPU frequency patches I sent, trying to detect
above and tell the user about an old or broken BIOS nicely illustrates
how useful this is?
People (including myself) waste hours of time disassembling acpi tables
and digging in the kernel code why the CPU which is supposed to be
CPU frequency capable cannot switch frequencies.
Latest examples posted on the cpufreq list:
Subject:
Re: [PATCH] Re: cpufreq limits avilable frequencies to 800MHz on git kernel
After the guy tried some patches and people went through his ACPI tables:
...
[ 8.168008] acpi-cpufreq: acpi_cpufreq_cpu_init
[ 8.168008] cpufreq-core: initialization failed
...
and finally:
=================
Thomas Renninger wrote:
> It looks like your BIOS is missing important cpufreq ACPI functions.
> Have you already checked whether your BIOS is up to date?
>
That was it, thanks, seems to be working now. I used flashrom from
coreboot for it...
Laurence
=================
or the guy who thought CPU frequency scaling is broken on Linux because
Microsoft shows 200MHz or similar:
Subject (on acpi and lk ml):
Re: cpufreq doesn't seem to work in Intel Q9300
This ended in a maybe 20 posts long useless discussion on linux-acpi and lkml.
If there is no _PSS function, the BIOS is broken. Updating it is the first
thing to do, no need to post anything before this step is done.
In this case there is also no need to discuss and debug that any further or
over and over again.
Thomas
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