[PATCH ] Add documentation on AMD powernow drivers

[PATCH ] Add documentation on AMD powernow drivers

[paul.devriendt]

Dave,

Please add a little piece of explanatory doc, as suggested by Dominik. Thanks.

Paul

diff -r -u --new-file linux-2.6.6/Documentation/cpu-freq/amd-powernow.txt linux-2.6.6.paul/Documentation/cpu-freq/amd-powernow.txt
--- linux-2.6.6/Documentation/cpu-freq/amd-powernow.txt	1969-12-31 18:00:00.000000000 -0600
+++ linux-2.6.6.paul/Documentation/cpu-freq/amd-powernow.txt	2004-06-10 10:55:31.000000000 -0500
@@ -0,0 +1,37 @@
+
+PowerNow! and Cool'n'Quiet are AMD names for frequency
+management capabilities in AMD processors. As the hardware
+implementation changes in new generations of the processors,
+there is a different cpu-freq driver for each generation.
+
+Note that the driver's will not load on the "wrong" hardware,
+so it is safe to try each driver in turn when in doubt as to
+which is the correct driver.
+
+Note that the functionality to change frequency (and voltage)
+is not available in all processors. The drivers will refuse
+to load on processors without this capability. The capability
+is detected with the cpuid instruction.
+
+The drivers use BIOS supplied tables to obtain frequency and
+voltage information appropriate for a particular platform.
+Frequency transitions will be unavailable if the BIOS does
+not supply these tables.
+
+6th Generation: powernow-k6
+
+7th Generation: powernow-k7: Athlon, Duron, Geode.
+
+8th Generation: powernow-k8: Athlon, Athlon 64, Opteron, Sempron.
+Documentation on this functionality in 8th generation processors
+is available in the "BIOS and Kernel Developer's Guide", publication
+26094, in chapter 9, available for download from www.amd.com <www.amd.com> . 
+
+BIOS supplied data, for powernow-k7 and for powernow-k8, may be
+from either the PSB table or from ACPI objects. The ACPI support
+is only available if the kernel config sets CONFIG_ACPI_PROCESSOR.
+The powernow-k8 driver will attempt to use ACPI if so configured,
+and fall back to PST if that fails.
+The powernow-k7 driver will try to use the PSB support first, and
+fall back to ACPI if the PSB support fails.
+

Re: [PATCH ] Add documentation on AMD powernow drivers

[Dave Jones]

On Thu, 2004-06-10 at 18:24, paul.devriendt@amd.com wrote:

> +6th Generation: powernow-k6
> +
> +7th Generation: powernow-k7: Athlon, Duron, Geode.
> +
> +8th Generation: powernow-k8: Athlon, Athlon 64, Opteron, Sempron.

The fact that 'Athlon' appears in both may be confusing to some readers.
Can this be further qualified ?   Athlon (family 15) or the like maybe?
Is the marketing name for those 32bit k8's just going to be athlon,
and not athlon-something? 

	Dave

Re: [PATCH ] Add documentation on AMD powernow drivers

[Andi Kleen]

Dave Jones <davej@redhat.com> writes:

> On Thu, 2004-06-10 at 18:24, paul.devriendt@amd.com wrote:
>
>> +6th Generation: powernow-k6
>> +
>> +7th Generation: powernow-k7: Athlon, Duron, Geode.
>> +
>> +8th Generation: powernow-k8: Athlon, Athlon 64, Opteron, Sempron.
>
> The fact that 'Athlon' appears in both may be confusing to some readers.
> Can this be further qualified ?   Athlon (family 15) or the like maybe?
> Is the marketing name for those 32bit k8's just going to be athlon,
> and not athlon-something? 

There are already K8 based Athlon XPs in some HP laptops.

I thought the name for the future 32bit K8s was "Sempron" though,
but I may be wrong.

-Andi

RE: [PATCH ] Add documentation on AMD powernow drivers

[paul.devriendt]

 
> The fact that 'Athlon' appears in both may be confusing to 
> some readers.
> Can this be further qualified ?   Athlon (family 15) or the 
> like maybe?
> Is the marketing name for those 32bit k8's just going to be athlon,
> and not athlon-something? 
> 
> 	Dave

I am afraid not ... the -something is not sufficient to tell. 
You need to go to the cpuid values, or look up the product number.
You need code to get the cpuid value, and the product number is
under the heat sink.

If you do not know, you have to try both drivers, and rely on the
cpuid checking in the driver.

Paul.