Commit 97b31c1f authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Pavel Machek
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leds: trigger: Disable CPU trigger on PREEMPT_RT 



The CPU trigger is invoked on ARM from CPU-idle. That trigger later
invokes led_trigger_event() which may invoke the callback of the actual driver.
That driver can acquire a spinlock_t which is okay on kernel without
PREEMPT_RT. On a PREEMPT_RT enabled kernel this lock is turned into a
sleeping lock and must not be acquired with disabled interrupts.

Disable the CPU trigger on PREEMPT_RT.

Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lkml.kernel.org/r/20210924111501.m57cwwn7ahiyxxdd@linutronix.de


Signed-off-by: default avatarPavel Machek <pavel@ucw.cz>
parent 2a5a8fa8

drivers/leds/trigger/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -64,6 +64,7 @@ config LEDS_TRIGGER_BACKLIGHT 


config LEDS_TRIGGER_CPU

	bool "LED CPU Trigger"

	depends on !PREEMPT_RT

	help

	  This allows LEDs to be controlled by active CPUs. This shows

	  the active CPUs across an array of LEDs so you can see which