On Wed, Aug 15, 2012 at 9:44 PM, Fabio Baltieri
<fabio.baltieri@xxxxxxxxx> wrote:
> Delay execution of led_set_brightness() if need to stop soft-blink
> timer.
>
> This allows led_set_brightness to be called in hard-irq context even if
> soft-blink was activated on that LED.
>
> Signed-off-by: Fabio Baltieri <fabio.baltieri@xxxxxxxxx>
> Cc: Pawel Moll <pawel.moll@xxxxxxx>
> Cc: Bryan Wu <bryan.wu@xxxxxxxxxxxxx>
> ---
>
> Hello Bryan,
>
> this version fixes the race in trigger change code and adds proper cleanup
> functions in unregister code path.
>
> Also, stop_blink code is now in a separe function declared in the local include
> file - it should not be needed for external triggers as the stop happens
> automatically for triggers trough set_brightess and trigger_event, through
> trigger change and unload functions requires it to be executed undelayed to
> work properly.
>
> I re-run all the test I had with this patch, including:
>
> - setting/resetting/changing trigger from timer/oneshot and none (which was I
> broke in V1)
>
> - mixed trigger from hard-irq: that's a snipped of the hacked code I used:
>
> if ((jiffies / HZ / 2) & 1)
> led_trigger_blink_oneshot(ledtrig_ide,
> &ide_blink_delay, &ide_blink_delay, 0);
> if ((jiffies / HZ / 4) & 1)
> led_trigger_event(ledtrig_ide, 100);
> if ((jiffies / HZ / 8) & 1)
> led_trigger_event(ledtrig_ide, 0);
>
> called repetedly from my sound-card irq handler while playing. The result is
> something like: 2s off, 2s blink, 4s on, 8s off.
>
> - mixed set_blink/set_brightness from the power_supply trigger (which was one
> who needed the original patch)
>
> - the CAN trigger I'm working on
>
> - some load/unload of my LED device driver
>
> - a bit of ftrace :-)
>
> the only thing I'm missing is testing on a real SMP system (I got an UP with
> CONFIG_SMP=y), but the critical part is unchanged so that should be ok.
>
> If that patch is ok, I think that we may also unify triggers to use only
> led_set_brightness in the future, as that now falls back automatically to
> __led_set_brightness if only direct-setting is used.
>
> Would you please consider this patch to replace the v1 currently in your
> for-next branch?
>
Thanks a lot for this update, I've applied to my for-next to replace
the v1 patch.
-Bryan
> Fabio
>
> drivers/leds/led-class.c | 15 +++++++++++++++
> drivers/leds/led-core.c | 16 +++++++++++++---
> drivers/leds/led-triggers.c | 4 +++-
> drivers/leds/leds.h | 2 ++
> include/linux/leds.h | 4 ++++
> 5 files changed, 37 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
> index c599095..48cce18 100644
> --- a/drivers/leds/led-class.c
> +++ b/drivers/leds/led-class.c
> @@ -124,6 +124,16 @@ static void led_timer_function(unsigned long data)
> mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay));
> }
>
> +static void set_brightness_delayed(struct work_struct *ws)
> +{
> + struct led_classdev *led_cdev =
> + container_of(ws, struct led_classdev, set_brightness_work);
> +
> + led_stop_software_blink(led_cdev);
> +
> + __led_set_brightness(led_cdev, led_cdev->delayed_set_value);
> +}
> +
> /**
> * led_classdev_suspend - suspend an led_classdev.
> * @led_cdev: the led_classdev to suspend.
> @@ -191,6 +201,8 @@ int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
>
> led_update_brightness(led_cdev);
>
> + INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed);
> +
> init_timer(&led_cdev->blink_timer);
> led_cdev->blink_timer.function = led_timer_function;
> led_cdev->blink_timer.data = (unsigned long)led_cdev;
> @@ -221,7 +233,10 @@ void led_classdev_unregister(struct led_classdev *led_cdev)
> up_write(&led_cdev->trigger_lock);
> #endif
>
> + cancel_work_sync(&led_cdev->set_brightness_work);
> +
> /* Stop blinking */
> + led_stop_software_blink(led_cdev);
> led_set_brightness(led_cdev, LED_OFF);
>
> device_unregister(led_cdev->dev);
> diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
> index 2ab05af..ce8921a 100644
> --- a/drivers/leds/led-core.c
> +++ b/drivers/leds/led-core.c
> @@ -103,13 +103,23 @@ void led_blink_set_oneshot(struct led_classdev *led_cdev,
> }
> EXPORT_SYMBOL(led_blink_set_oneshot);
>
> -void led_set_brightness(struct led_classdev *led_cdev,
> - enum led_brightness brightness)
> +void led_stop_software_blink(struct led_classdev *led_cdev)
> {
> - /* stop and clear soft-blink timer */
> del_timer_sync(&led_cdev->blink_timer);
> led_cdev->blink_delay_on = 0;
> led_cdev->blink_delay_off = 0;
> +}
> +EXPORT_SYMBOL_GPL(led_stop_software_blink);
> +
> +void led_set_brightness(struct led_classdev *led_cdev,
> + enum led_brightness brightness)
> +{
> + /* delay brightness setting if need to stop soft-blink timer */
> + if (led_cdev->blink_delay_on || led_cdev->blink_delay_off) {
> + led_cdev->delayed_set_value = brightness;
> + schedule_work(&led_cdev->set_brightness_work);
> + return;
> + }
>
> __led_set_brightness(led_cdev, brightness);
> }
> diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
> index 363975b..b53bf54 100644
> --- a/drivers/leds/led-triggers.c
> +++ b/drivers/leds/led-triggers.c
> @@ -109,6 +109,8 @@ void led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)
> list_del(&led_cdev->trig_list);
> write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock,
> flags);
> + cancel_work_sync(&led_cdev->set_brightness_work);
> + led_stop_software_blink(led_cdev);
> if (led_cdev->trigger->deactivate)
> led_cdev->trigger->deactivate(led_cdev);
> led_cdev->trigger = NULL;
> @@ -224,7 +226,7 @@ void led_trigger_event(struct led_trigger *trig,
> struct led_classdev *led_cdev;
>
> led_cdev = list_entry(entry, struct led_classdev, trig_list);
> - __led_set_brightness(led_cdev, brightness);
> + led_set_brightness(led_cdev, brightness);
> }
> read_unlock(&trig->leddev_list_lock);
> }
> diff --git a/drivers/leds/leds.h b/drivers/leds/leds.h
> index d02acd4..4c50365 100644
> --- a/drivers/leds/leds.h
> +++ b/drivers/leds/leds.h
> @@ -32,6 +32,8 @@ static inline int led_get_brightness(struct led_classdev *led_cdev)
> return led_cdev->brightness;
> }
>
> +void led_stop_software_blink(struct led_classdev *led_cdev);
> +
> extern struct rw_semaphore leds_list_lock;
> extern struct list_head leds_list;
>
> diff --git a/include/linux/leds.h b/include/linux/leds.h
> index 3aade1d..5676197 100644
> --- a/include/linux/leds.h
> +++ b/include/linux/leds.h
> @@ -16,6 +16,7 @@
> #include <linux/spinlock.h>
> #include <linux/rwsem.h>
> #include <linux/timer.h>
> +#include <linux/workqueue.h>
>
> struct device;
> /*
> @@ -69,6 +70,9 @@ struct led_classdev {
> struct timer_list blink_timer;
> int blink_brightness;
>
> + struct work_struct set_brightness_work;
> + int delayed_set_value;
> +
> #ifdef CONFIG_LEDS_TRIGGERS
> /* Protects the trigger data below */
> struct rw_semaphore trigger_lock;
> --
> 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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