On 04/06/2016 06:38 AM, Ezequiel Garcia wrote:
On 5 April 2016 at 18:36, Jacek Anaszewski <jacek.anaszewski@xxxxxxxxx> wrote:
Hi Ezequiel,
On 04/04/2016 10:22 PM, Ezequiel Garcia wrote:
Now that we can mark any LED (even those in use by delayed blink
triggers) to trigger on a kernel panic, let's introduce a nosleep
led_trigger_event API.
This API is needed to skip the delayed blink path on
led_trigger_event. LEDs that are switched on a kernel panic,
might be in use by a delayed blink trigger.
This will be used by the panic LED trigger.
Signed-off-by: Ezequiel Garcia <ezequiel@xxxxxxxxxxxxxxxxxxxx>
---
drivers/leds/led-triggers.c | 26 ++++++++++++++++++++++----
include/linux/leds.h | 4 ++++
2 files changed, 26 insertions(+), 4 deletions(-)
diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
index f5c9d7c4d181..00b9d8497777 100644
--- a/drivers/leds/led-triggers.c
+++ b/drivers/leds/led-triggers.c
@@ -307,8 +307,9 @@ EXPORT_SYMBOL_GPL(devm_led_trigger_register);
/* Simple LED Tigger Interface */
-void led_trigger_event(struct led_trigger *trig,
- enum led_brightness brightness)
+static void do_led_trigger_event(struct led_trigger *trig,
+ enum led_brightness brightness,
+ bool nosleep)
{
struct led_classdev *led_cdev;
@@ -316,12 +317,29 @@ void led_trigger_event(struct led_trigger *trig,
return;
read_lock(&trig->leddev_list_lock);
- list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list)
- led_set_brightness(led_cdev, brightness);
led_set_brightness() can gently disable blinking if passed 0 in the
brightness argument. IMHO this patch is not needed then.
Yes, but the blinking disable is deferred, and so might never
run (e.g. I'd say it won't run on a non-preemptible kernel).
I think we need this API, or otherwise some way of circumventing
the deferred path on led_set_brightness. For instance, we
could turn off delay_on and delay_off in the panic atomic notifier.
Yes, I prefer the latter, as it requires less changes.
I'm not strongly convinced by any approach, but this API seemed
slightly cleaner.
--
Best regards,
Jacek Anaszewski
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