On 04/27/2014 06:41 PM, MyungJoo Ham wrote:
>> Some devices use freq_table instead of OPP. For those devices, the
>> available_frequencies file shows up empty. Fix that by using freq_table to
>> generate the available_frequencies data when it's available.
>>
>> OPP find frequency APIs also skips frequencies that have been temporarily
>> disabled (say, due to thermal, etc). Since available_frequencies is
>> supposed to show the entire list of available frequencies without taking
>> temporary limits into consideration, preference is given to freq_table when
>> available.
>>
>> Signed-off-by: Saravana Kannan <skannan@xxxxxxxxxxxxxx>
>> ---
>> drivers/devfreq/devfreq.c | 29 ++++++++++++++++++-----------
>> 1 file changed, 18 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>> index 2042ec3..527cbe2 100644
>> --- a/drivers/devfreq/devfreq.c
>> +++ b/drivers/devfreq/devfreq.c
>> @@ -912,20 +912,27 @@ static ssize_t available_frequencies_show(struct device *d,
>> struct devfreq *df = to_devfreq(d);
>> struct device *dev = df->dev.parent;
>> struct dev_pm_opp *opp;
>> + unsigned int i = 0;
>> ssize_t count = 0;
>> unsigned long freq = 0;
>>
>> - rcu_read_lock();
>> - do {
>> - opp = dev_pm_opp_find_freq_ceil(dev, &freq);
>> - if (IS_ERR(opp))
>> - break;
>> -
>> - count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
>> - "%lu ", freq);
>> - freq++;
>> - } while (1);
>> - rcu_read_unlock();
>> + if (df->profile->freq_table) {
>> + for (i = 0; i < df->profile->max_state; i++)
>> + count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
>> + "%u ", df->profile->freq_table[i]);
>
> You are hereby changing the semmantics of the original
> available_frequencies node.
>
> When a frequency/voltage pair has been disabled (opp_disable), probably
> by opp_disable(), the frequency is no more "available".
> However, when the driver author supplied freq_table as well as OPP
> in order to see the statistics, the node will behave differently.
>
> Please do not affect the current users as long as it does not give
> additional benefit or fix a bug.
I was actually trying to stick with the semantics as it was documented.
The documentation for this file says it'll show frequencies that are not
allowed by the current min/max settings either. To me, an OPP disable
seems similar to some frequencies "disabled" by min/max settings.
Giving preference to OPP is not a hard change to do, but it seems to go
againsts the documented semantics.
Thoughts?
-Saravana
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