On 15-01-2014 07:26, Wei Ni wrote: > On 01/13/2014 11:58 PM, Eduardo Valentin wrote: >> * PGP Signed by an unknown key >> >> On 13-01-2014 07:17, Wei Ni wrote: >>> The Linux thermal framework support to change governor policy >>> in run time, but it can't show what available policies supported. >>> >>> This patch adds available_policies attribut to the thermal >> >> s/attribut/attribute/g > > oh, thanks, I will fix it. > >> >>> framework, it can list the thermal governors which can be >>> used for a particular zone. This attribut is read only. >>> >>> Signed-off-by: Wei Ni <[email protected]> >>> --- >>> Documentation/thermal/sysfs-api.txt | 6 ++++++ >>> drivers/thermal/thermal_core.c | 25 +++++++++++++++++++++++++ >>> 2 files changed, 31 insertions(+) >>> >>> diff --git a/Documentation/thermal/sysfs-api.txt >>> b/Documentation/thermal/sysfs-api.txt >>> index 87519cb..6a70b55c 100644 >>> --- a/Documentation/thermal/sysfs-api.txt >>> +++ b/Documentation/thermal/sysfs-api.txt >>> @@ -172,6 +172,7 @@ Thermal zone device sys I/F, created once it's >>> registered: >>> |---temp: Current temperature >>> |---mode: Working mode of the thermal zone >>> |---policy: Thermal governor used for this zone >>> + |---available_policies Available governors for this zone >> >> I would prefer: >> "Available thermal governors for this zone" > > Ok. > >> >>> |---trip_point_[0-*]_temp: Trip point temperature >>> |---trip_point_[0-*]_type: Trip point type >>> |---trip_point_[0-*]_hyst: Hysteresis value for this trip point >>> @@ -238,6 +239,10 @@ policy >>> One of the various thermal governors used for a particular zone. >>> RW, Required >>> >>> +available_policies >>> + Availabe thermal governors which can be used for a particular zone. >>> + RO, Required >>> + >>> trip_point_[0-*]_temp >>> The temperature above which trip point will be fired. >>> Unit: millidegree Celsius >>> @@ -330,6 +335,7 @@ method, the sys I/F structure will be built like this: >>> |---temp: 37000 >>> |---mode: enabled >>> |---policy: step_wise >>> + |---available_policies: step_wise fair_share >>> |---trip_point_0_temp: 100000 >>> |---trip_point_0_type: critical >>> |---trip_point_1_temp: 80000 >>> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c >>> index 338a88b..aab1df8 100644 >>> --- a/drivers/thermal/thermal_core.c >>> +++ b/drivers/thermal/thermal_core.c >>> @@ -761,6 +761,24 @@ policy_show(struct device *dev, struct >>> device_attribute *devattr, char *buf) >>> return sprintf(buf, "%s\n", tz->governor->name); >>> } >>> >>> +static ssize_t >>> +available_policies_show(struct device *dev, struct device_attribute >>> *devattr, >>> + char *buf) >>> +{ >>> + struct thermal_governor *pos; >>> + ssize_t count = 0; >>> + >>> + mutex_lock(&thermal_governor_lock); >>> + >>> + list_for_each_entry(pos, &thermal_governor_list, governor_list) >>> + count += sprintf(buf + count, "%s ", pos->name); >> >> I would prefer if you'd used scnprintf >> >>> + count += sprintf(buf + count, "\n"); >> >> ditto. >> >> >> It is unlikely, but What if count if greater than PAGE_SIZE? > > hmm, I checked the sysfs driver, in funciton sysfs_kf_seq_show(), it > seems it can handle the count greater than PAGE_SIZE. > Or we can return error here directly. > What do you think about it?
Just to be aware that it will truncate your buffer:
/*
* The code works fine with PAGE_SIZE return but it's likely to
* indicate truncated result or overflow in normal use cases.
*/
if (count >= (ssize_t)PAGE_SIZE) {
print_symbol("fill_read_buffer: %s returned bad count\n",
(unsigned long)ops->show);
/* Try to struggle along */
count = PAGE_SIZE - 1;
}
So, you either truncate here or leave to sysfs_seq_show(). Leave at
least a comment in case you leave to sysfs layer.
>
>>
>>> +
>>> + mutex_unlock(&thermal_governor_lock);
>>> +
>>> + return count;
>>> +}
>>> +
>>> #ifdef CONFIG_THERMAL_EMULATION
>>> static ssize_t
>>> emul_temp_store(struct device *dev, struct device_attribute *attr,
>>> @@ -794,6 +812,7 @@ static DEVICE_ATTR(temp, 0444, temp_show, NULL);
>>> static DEVICE_ATTR(mode, 0644, mode_show, mode_store);
>>> static DEVICE_ATTR(passive, S_IRUGO | S_IWUSR, passive_show,
>>> passive_store);
>>> static DEVICE_ATTR(policy, S_IRUGO | S_IWUSR, policy_show, policy_store);
>>> +static DEVICE_ATTR(available_policies, S_IRUGO, available_policies_show,
>>> NULL);
>>>
>>> /* sys I/F for cooling device */
>>> #define to_cooling_device(_dev) \
>>> @@ -1527,6 +1546,11 @@ struct thermal_zone_device
>>> *thermal_zone_device_register(const char *type,
>>> if (result)
>>> goto unregister;
>>>
>>> + /* Create available_policies attribute */
>>> + result = device_create_file(&tz->device, &dev_attr_available_policies);
>>> + if (result)
>>> + goto unregister;
>>> +
>>> /* Update 'this' zone's governor information */
>>> mutex_lock(&thermal_governor_lock);
>>>
>>> @@ -1622,6 +1646,7 @@ void thermal_zone_device_unregister(struct
>>> thermal_zone_device *tz)
>>> if (tz->ops->get_mode)
>>> device_remove_file(&tz->device, &dev_attr_mode);
>>> device_remove_file(&tz->device, &dev_attr_policy);
>>> + device_remove_file(&tz->device, &dev_attr_available_policies);
>>> remove_trip_attrs(tz);
>>> tz->governor = NULL;
>>>
>>>
>>
>>
>
>
>
--
You have got to be excited about what you are doing. (L. Lamport)
Eduardo Valentin
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