Re: [PATCH] cleanup LED documentation and make it match reality

Jacek Anaszewski
2016-10-19T14:56:31Z

On 10/03/2016 11:38 AM, Pavel Machek wrote:
> Hi!
>
>> Thanks for the patch.
>>
>> On 10/03/2016 10:10 AM, Pavel Machek wrote:
>>>
>>> sysfs-class-led fails to mention some important details. Also fix led
>>> vs LED and english.
>>>
>>> Signed-off-by: Pavel Machek <pavel@ucw.cz>
>>>
>>> --- a/Documentation/ABI/testing/sysfs-class-led
>>> +++ b/Documentation/ABI/testing/sysfs-class-led
>>> @@ -4,16 +4,25 @@ KernelVersion: 2.6.17
>>> Contact: Richard Purdie <rpurdie@rpsys.net>
>>> Description:
>>> Set the brightness of the LED. Most LEDs don't
>>> - have hardware brightness support so will just be turned on for
>>> + have hardware brightness support, so will just be turned on for
>>> non-zero brightness settings. The value is between 0 and
>>> /sys/class/leds/<led>/max_brightness.
>>>
>>> + Writing 0 to this file clears active trigger.
>>> +
>>> + Writing non-zero to this file while trigger is active changes the
>>> + top brightness trigger is going to use.
>>
>> This is true only in case of timer trigger, as it uses blink_brightness
>> property from struct led_classdev to cache current brightness, when the
>> the LED is in the off cycle. This is part of software blink fallback
>> functionality.
>>
>> In case of heartbeat trigger max_brightness is always used for top level
>> brightness. We'd need to refactor the trigger a bit to allow for
>> different top brightness levels.
>
> Ok, do you think you could update the documenation to match the
> reality? It is quite important to know what is the intended behaviour
> and what are the bugs.

Applied the patch (removed extra empty line) after improving heartbeat
trigger [0] to support brightness levels other then max_brightness.

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