diff options
| author | Matthew Garrett <mjg@redhat.com> | 2008-11-25 13:29:47 -0500 |
|---|---|---|
| committer | Dave Jones <davej@redhat.com> | 2008-12-05 15:20:10 -0500 |
| commit | e088e4c9cdb618675874becb91b2fd581ee707e6 (patch) | |
| tree | 48231c406061308502f13c7781a6957ef396a739 | |
| parent | 10db2e5cbda5b4e13d2e2f134b963bee2e129999 (diff) | |
| download | linux-3.10-e088e4c9cdb618675874becb91b2fd581ee707e6.tar.gz linux-3.10-e088e4c9cdb618675874becb91b2fd581ee707e6.tar.bz2 linux-3.10-e088e4c9cdb618675874becb91b2fd581ee707e6.zip | |
[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>
| -rw-r--r-- | arch/x86/kernel/cpu/cpufreq/p4-clockmod.c | 1 | ||||
| -rw-r--r-- | drivers/cpufreq/cpufreq.c | 51 | ||||
| -rw-r--r-- | include/linux/cpufreq.h | 1 |
3 files changed, 35 insertions, 18 deletions
diff --git a/arch/x86/kernel/cpu/cpufreq/p4-clockmod.c b/arch/x86/kernel/cpu/cpufreq/p4-clockmod.c index ba3a94a997c..0c43b224051 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, }; diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 31d6f535a79..9044b911d8a 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -754,6 +754,11 @@ static struct kobj_type ktype_cpufreq = { .release = cpufreq_sysfs_release, }; +static struct kobj_type ktype_empty_cpufreq = { + .sysfs_ops = &sysfs_ops, + .release = cpufreq_sysfs_release, +}; + /** * cpufreq_add_dev - add a CPU device @@ -876,26 +881,36 @@ static int cpufreq_add_dev(struct sys_device *sys_dev) memcpy(&new_policy, policy, sizeof(struct cpufreq_policy)); /* prepare interface data */ - ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, &sys_dev->kobj, - "cpufreq"); - if (ret) - goto err_out_driver_exit; - - /* set up files for this cpu device */ - drv_attr = cpufreq_driver->attr; - while ((drv_attr) && (*drv_attr)) { - ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr)); + if (!cpufreq_driver->hide_interface) { + ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, + &sys_dev->kobj, "cpufreq"); if (ret) goto err_out_driver_exit; - drv_attr++; - } - if (cpufreq_driver->get) { - ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr); - if (ret) - goto err_out_driver_exit; - } - if (cpufreq_driver->target) { - ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr); + + /* set up files for this cpu device */ + drv_attr = cpufreq_driver->attr; + while ((drv_attr) && (*drv_attr)) { + ret = sysfs_create_file(&policy->kobj, + &((*drv_attr)->attr)); + if (ret) + goto err_out_driver_exit; + drv_attr++; + } + if (cpufreq_driver->get) { + ret = sysfs_create_file(&policy->kobj, + &cpuinfo_cur_freq.attr); + if (ret) + goto err_out_driver_exit; + } + if (cpufreq_driver->target) { + ret = sysfs_create_file(&policy->kobj, + &scaling_cur_freq.attr); + if (ret) + goto err_out_driver_exit; + } + } else { + ret = kobject_init_and_add(&policy->kobj, &ktype_empty_cpufreq, + &sys_dev->kobj, "cpufreq"); if (ret) goto err_out_driver_exit; } diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index 1ee608fd7b7..484b3abf61b 100644 --- a/include/linux/cpufreq.h +++ b/include/linux/cpufreq.h @@ -234,6 +234,7 @@ struct cpufreq_driver { int (*suspend) (struct cpufreq_policy *policy, pm_message_t pmsg); int (*resume) (struct cpufreq_policy *policy); struct freq_attr **attr; + bool hide_interface; }; /* flags */ |