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authorMatthew Garrett <mjg@redhat.com>2008-11-25 13:29:47 -0500
committerDave Jones <davej@redhat.com>2008-12-05 15:20:10 -0500
commite088e4c9cdb618675874becb91b2fd581ee707e6 (patch)
tree48231c406061308502f13c7781a6957ef396a739 /arch/x86/kernel/cpu/cpufreq/p4-clockmod.c
parent10db2e5cbda5b4e13d2e2f134b963bee2e129999 (diff)
[CPUFREQ] Disable sysfs ui for p4-clockmod.
p4-clockmod has a long history of abuse. It pretends to be a CPU frequency scaling driver, even though it doesn't actually change the CPU frequency, but instead just modulates the frequency with wait-states. The biggest misconception is that when running at the lower 'frequency' p4-clockmod is saving power. This isn't the case, as workloads running slower take longer to complete, preventing the CPU from entering deep C states. However p4-clockmod does have a purpose. It can prevent overheating. Having it hooked up to the cpufreq interfaces is the wrong way to achieve cooling however. It should instead be hooked up to ACPI. This diff introduces a means for a cpufreq driver to register with the cpufreq core, but not present a sysfs interface. Signed-off-by: Matthew Garrett <mjg@redhat.com> Signed-off-by: Dave Jones <davej@redhat.com>
Diffstat (limited to 'arch/x86/kernel/cpu/cpufreq/p4-clockmod.c')
-rw-r--r--arch/x86/kernel/cpu/cpufreq/p4-clockmod.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/cpufreq/p4-clockmod.c b/arch/x86/kernel/cpu/cpufreq/p4-clockmod.c
index ba3a94a997c3..0c43b2240517 100644
--- a/arch/x86/kernel/cpu/cpufreq/p4-clockmod.c
+++ b/arch/x86/kernel/cpu/cpufreq/p4-clockmod.c
@@ -276,6 +276,7 @@ static struct cpufreq_driver p4clockmod_driver = {
.name = "p4-clockmod",
.owner = THIS_MODULE,
.attr = p4clockmod_attr,
+ .hide_interface = 1,
};