Re: [PATCH v2] leds: fix led_brightness_set when soft-blinking

From: Bryan Wu
Date: Wed Jun 06 2012 - 04:19:31 EST


On Wed, Jun 6, 2012 at 3:19 PM, Fabio Baltieri <fabio.baltieri@xxxxxxxxx> wrote:
> Put del_timer_sync() back into led_stop_software_blink() and move the
> call earlier into led_blink_set() to ensure software blink timer is
> stopped when changing trigger.  Also use led_set_brightness() instead of
> calling led_cdev->brightness_set() directly to ensure
> led_cdev->brightness is always consistent with current LED status.
>
> This ensure proper cleaning when changing triggers, as without this fix
> a LED may be turned off while leaving it's led_cdev->brightness = 1,
> leading to an erratic software-blink behaviour.
>
> The problem was easy to reproduce by changing the trigger from "timer"
> to "oneshot".
>
> Signed-off-by: Fabio Baltieri <fabio.baltieri@xxxxxxxxx>
> Cc: Bryan Wu <bryan.wu@xxxxxxxxxxxxx>

Looks fine and actually a patch fixed similar issue before in my
fixes-for-3.5 branch.
http://git.kernel.org/?p=linux/kernel/git/cooloney/linux-leds.git;a=commitdiff;h=b2f819714f40a6593c1ed20b69573d5fef71f392
I plan to send out these fixes soon.

I have to rebase all patches in for-next on top of fixes, then I met
some conflicts. After fixing conflicts, I rebuilt the for-next tree
which contains 3 patches from you. Please grab it and test, I will try
that on my hardware.
http://git.kernel.org/?p=linux/kernel/git/cooloney/linux-leds.git;a=shortlog;h=refs/heads/for-next

Thanks,
-Bryan

> ---
>
> ...maybe that version makes more sense.
>
> Fabio
>
>  drivers/leds/led-core.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
> index 579eb78..2477109 100644
> --- a/drivers/leds/led-core.c
> +++ b/drivers/leds/led-core.c
> @@ -27,6 +27,7 @@ EXPORT_SYMBOL_GPL(leds_list);
>  static void led_stop_software_blink(struct led_classdev *led_cdev)
>  {
>        /* deactivate previous settings */
> +       del_timer_sync(&led_cdev->blink_timer);
>        led_cdev->blink_delay_on = 0;
>        led_cdev->blink_delay_off = 0;
>  }
> @@ -43,8 +44,6 @@ static void led_set_software_blink(struct led_classdev *led_cdev,
>        if (!led_cdev->blink_brightness)
>                led_cdev->blink_brightness = led_cdev->max_brightness;
>
> -       led_stop_software_blink(led_cdev);
> -
>        led_cdev->blink_delay_on = delay_on;
>        led_cdev->blink_delay_off = delay_off;
>
> @@ -82,7 +81,7 @@ void led_blink_set(struct led_classdev *led_cdev,
>                   unsigned long *delay_on,
>                   unsigned long *delay_off)
>  {
> -       del_timer_sync(&led_cdev->blink_timer);
> +       led_stop_software_blink(led_cdev);
>
>        led_cdev->flags &= ~LED_BLINK_ONESHOT;
>        led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP;
> @@ -116,6 +115,6 @@ void led_brightness_set(struct led_classdev *led_cdev,
>                        enum led_brightness brightness)
>  {
>        led_stop_software_blink(led_cdev);
> -       led_cdev->brightness_set(led_cdev, brightness);
> +       led_set_brightness(led_cdev, brightness);
>  }
>  EXPORT_SYMBOL(led_brightness_set);
> --
> 1.7.11.rc1.9.gf623ca1.dirty
>



--
Bryan Wu <bryan.wu@xxxxxxxxxxxxx>
Kernel Developer    +86.186-168-78255 Mobile
Canonical Ltd.      www.canonical.com
Ubuntu - Linux for human beings | www.ubuntu.com
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