linux-kernel - Re: [PATCH v2] leds: fix led_brightness

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Date:	Thu, 7 Jun 2012 20:58:03 +0800
From:	Bryan Wu <bryan.wu@...onical.com>
To:	shuahkhan@...il.com
Cc:	Fabio Baltieri <fabio.baltieri@...il.com>,
	linux-leds@...r.kernel.org, linux-kernel@...r.kernel.org,
	Richard Purdie <rpurdie@...ys.net>
Subject: Re: [PATCH v2] leds: fix led_brightness_set when soft-blinking

On Thu, Jun 7, 2012 at 4:30 AM, Shuah Khan <shuahkhan@...il.com> wrote:
>
>> I realize now that my last patch broke ledtrig-timer updates as that
>> works by passing delay_{on,off} values by pointer, and moving
>> led_stop_software_blink() earlier destroy the other value.
>
> Fabio,
>
> This type of interaction is what I am concerned about, and came up
> during the transient trigger discussion as well. In the case of
> transient trigger it was an easy decision to use separate namespace, but
> that doesn't make sense in this case.
>
>>
>> That's a bit of a pitfall, as the old code was working because values
>> were copied when entering led_set_software_blink.
>>
>> I see three options here:
>> - reverting back my leds: "fix led_brightness_set when soft-blinking"
>>   (9b05cd0) to the first version I posted, wich should work as before.
>> - modify ledtrig-timer to use two internal variables to store delay_on
>>   and delay_off instead of the led_cdev ones.
>
> Don't this this is a viable option without restructuring the leds code.
> These two variables are common to led_cdev and used by other drivers as
> well. ledtrig-timer will still have to store it as these are used in the
> led_timer_function() in led-class.c
>
>> - moving the two led_cdev->blink_delay_xx = 0 only into
>>   led_brightness_set, as that's the only place when they are needed.
>
> Sounds reasonable. I would like to pull your patches in and do some
> testing, but very likely I won't be able to get to it until this
> weekend. This is where use-cases will help as well for us go through
> various transitions and see if it all comes together.
>

Hi Fabio, thanks for updating this. I've added use the v3 replace the
old one in my for-next and devel branches

Shuah, Thanks for reviewing, if you wanna try this, just grab patches
from devel branch.

-Bryan



-- 
Bryan Wu <bryan.wu@...onical.com>
Kernel Developer    +86.186-168-78255 Mobile
Canonical Ltd.      www.canonical.com
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