diff options
| -rw-r--r-- | drivers/leds/led-triggers.c | 2 | ||||
| -rw-r--r-- | drivers/leds/leds.h | 1 | ||||
| -rw-r--r-- | drivers/leds/trigger/Kconfig | 3 | ||||
| -rw-r--r-- | drivers/leds/trigger/ledtrig-panic.c | 47 | ||||
| -rw-r--r-- | include/linux/leds.h | 1 |
5 files changed, 53 insertions, 1 deletions
diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c index 2181581795d3..55fa65e1ae03 100644 --- a/drivers/leds/led-triggers.c +++ b/drivers/leds/led-triggers.c @@ -26,7 +26,7 @@ * Nests outside led_cdev->trigger_lock */ static DECLARE_RWSEM(triggers_list_lock); -static LIST_HEAD(trigger_list); +LIST_HEAD(trigger_list); /* Used by LED Class */ diff --git a/drivers/leds/leds.h b/drivers/leds/leds.h index db3f20da7221..7d38e6b9a740 100644 --- a/drivers/leds/leds.h +++ b/drivers/leds/leds.h @@ -30,5 +30,6 @@ void led_set_brightness_nosleep(struct led_classdev *led_cdev, extern struct rw_semaphore leds_list_lock; extern struct list_head leds_list; +extern struct list_head trigger_list; #endif /* __LEDS_H_INCLUDED */ diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig index beac8c31c51b..9893d911390d 100644 --- a/drivers/leds/trigger/Kconfig +++ b/drivers/leds/trigger/Kconfig @@ -121,6 +121,9 @@ config LEDS_TRIGGER_PANIC depends on LEDS_TRIGGERS help This allows LEDs to be configured to blink on a kernel panic. + Enabling this option will allow to mark certain LEDs as panic indicators, + allowing to blink them on a kernel panic, even if they are set to + a different trigger. If unsure, say Y. endif # LEDS_TRIGGERS diff --git a/drivers/leds/trigger/ledtrig-panic.c b/drivers/leds/trigger/ledtrig-panic.c index 627b350c5ec3..d735526b9db4 100644 --- a/drivers/leds/trigger/ledtrig-panic.c +++ b/drivers/leds/trigger/ledtrig-panic.c @@ -11,10 +11,54 @@ #include <linux/kernel.h> #include <linux/init.h> +#include <linux/notifier.h> #include <linux/leds.h> +#include "../leds.h" static struct led_trigger *trigger; +/* + * This is called in a special context by the atomic panic + * notifier. This means the trigger can be changed without + * worrying about locking. + */ +static void led_trigger_set_panic(struct led_classdev *led_cdev) +{ + struct led_trigger *trig; + + list_for_each_entry(trig, &trigger_list, next_trig) { + if (strcmp("panic", trig->name)) + continue; + if (led_cdev->trigger) + list_del(&led_cdev->trig_list); + list_add_tail(&led_cdev->trig_list, &trig->led_cdevs); + + /* Avoid the delayed blink path */ + led_cdev->blink_delay_on = 0; + led_cdev->blink_delay_off = 0; + + led_cdev->trigger = trig; + if (trig->activate) + trig->activate(led_cdev); + break; + } +} + +static int led_trigger_panic_notifier(struct notifier_block *nb, + unsigned long code, void *unused) +{ + struct led_classdev *led_cdev; + + list_for_each_entry(led_cdev, &leds_list, node) + if (led_cdev->flags & LED_PANIC_INDICATOR) + led_trigger_set_panic(led_cdev); + return NOTIFY_DONE; +} + +static struct notifier_block led_trigger_panic_nb = { + .notifier_call = led_trigger_panic_notifier, +}; + static long led_panic_blink(int state) { led_trigger_event(trigger, state ? LED_FULL : LED_OFF); @@ -23,6 +67,9 @@ static long led_panic_blink(int state) static int __init ledtrig_panic_init(void) { + atomic_notifier_chain_register(&panic_notifier_list, + &led_trigger_panic_nb); + led_trigger_register_simple("panic", &trigger); panic_blink = led_panic_blink; return 0; diff --git a/include/linux/leds.h b/include/linux/leds.h index 19eb10278bea..7e9fb00e15e8 100644 --- a/include/linux/leds.h +++ b/include/linux/leds.h @@ -50,6 +50,7 @@ struct led_classdev { #define LED_SYSFS_DISABLE (1 << 22) #define LED_DEV_CAP_FLASH (1 << 23) #define LED_HW_PLUGGABLE (1 << 24) +#define LED_PANIC_INDICATOR (1 << 25) /* Set LED brightness level * Must not sleep. Use brightness_set_blocking for drivers |