Re: [PATCH 0/5] Add P state driver for Intel Core Processors

From: Dirk Brandewie
Date: Thu Feb 14 2013 - 10:23:54 EST

On 02/14/2013 04:21 AM, Rafael J. Wysocki wrote:
On Thursday, February 14, 2013 09:38:21 AM Viresh Kumar wrote:
On Wed, Feb 13, 2013 at 10:08 PM, Dirk Brandewie
<dirk.brandewie@xxxxxxxxx> wrote:
For the case where both are built-in the load order works my driver uses
device_initcall() and acpi_cpufreq uses late_initcall().

For the case where both are a module (which I was sure I tested) you are
I will have to do something.

For now I propose to make my driver built-in only while I sort out the right
solution for the module build. Does this seem reasonable to everyone?

Of-course i am missing something here. Why would anybody want to insert
acpi-cpufreq module when the system supports the pstate driver.

In case they are mutually exclusive, then we can have something like
depends on !ACPI-DRIVER in the kconfig option of pstate driver.

Yes. Or the other way around (i.e. make acpi_cpufreq depend on

The issue is that acpi-cpufreq still needs to be available for Intel processors before SandyBridge and for other x86 compatible processors we can't make
intel_pstate and acpi-cpufreq mutually exclusive.

Having intel_pstate built-in solves the issue without the need to patch
acpi-cpufreq. I believe that most distros build the scaling drivers in
so the distro/user will make the explicit decision to use intel_pstate.


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