diff options
| author | Viresh Kumar <viresh.kumar@linaro.org> | 2013-10-16 23:58:10 +0200 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2013-10-16 23:58:10 +0200 |
| commit | 1bab64d50e09706ee2e634b2df3c53346f0a0dbb (patch) | |
| tree | b7df2d323eb358e1633506ed360a191a41e1ae8d /drivers/cpufreq/acpi-cpufreq.c | |
| parent | 076dec90fc32c830184b0f0fa1842a6de1199bc6 (diff) | |
acpi-cpufreq: Add comment under ACPI_ADR_SPACE_SYSTEM_IO case
policy->cur is now set by cpufreq core when cpufreq_driver->get() is defined and
so drivers aren't required to set it. When space_id is ACPI_ADR_SPACE_SYSTEM_IO
for acpi cpufreq driver it doesn't set ->get to a valid function pointer and so
policy->cur is required to be set by driver.
This is already followed in acpi-cpufreq driver. This patch adds a comment
describing why we need to set policy->cur from driver.
Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq/acpi-cpufreq.c')
| -rw-r--r-- | drivers/cpufreq/acpi-cpufreq.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c index a8dac7b53042..a1717d7367c1 100644 --- a/drivers/cpufreq/acpi-cpufreq.c +++ b/drivers/cpufreq/acpi-cpufreq.c @@ -837,7 +837,12 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy) switch (perf->control_register.space_id) { case ACPI_ADR_SPACE_SYSTEM_IO: - /* Current speed is unknown and not detectable by IO port */ + /* + * The core will not set policy->cur, because + * cpufreq_driver->get is NULL, so we need to set it here. + * However, we have to guess it, because the current speed is + * unknown and not detectable via IO ports. + */ policy->cur = acpi_cpufreq_guess_freq(data, policy->cpu); break; case ACPI_ADR_SPACE_FIXED_HARDWARE: |