leds: class: Revert: "If no default trigger is given, make hw_control trigger the default trigger"

Commit 66601a2 ("leds: class: If no default trigger is given, make
hw_control trigger the default trigger") causes ledtrig-netdev to get
set as default trigger on various network LEDs.

This causes users to hit a pre-existing AB-BA deadlock issue in
ledtrig-netdev between the LED-trigger locks and the rtnl mutex,
resulting in hung tasks in kernels >= 6.9.

Solving the deadlock is non trivial, so for now revert the change to
set the hw_control trigger as default trigger, so that ledtrig-netdev
no longer gets activated automatically for various network LEDs.

The netdev trigger is not needed because the network LEDs are usually under
hw-control and the netdev trigger tries to leave things that way so setting
it as the active trigger for the LED class device is a no-op.

Fixes: 66601a2 ("leds: class: If no default trigger is given, make hw_control trigger the default trigger")
Reported-by: Genes Lists <[email protected]>
Closes: https://lore.kernel.org/all/[email protected]/
Reported-by: Johannes Wüller <[email protected]>
Closes: https://lore.kernel.org/lkml/[email protected]/
Cc: [email protected]
Signed-off-by: Hans de Goede <[email protected]>
Reviewed-by: Andrew Lunn <[email protected]>
Acked-by: Lee Jones <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Author: jwrdegoede

drivers/leds/led-class.c

@@ -552,12 +552,6 @@ int led_classdev_register_ext(struct device *parent,
 	led_init_core(led_cdev);
 
 #ifdef CONFIG_LEDS_TRIGGERS
-	/*
-	 * If no default trigger was given and hw_control_trigger is set,
-	 * make it the default trigger.
-	 */
-	if (!led_cdev->default_trigger && led_cdev->hw_control_trigger)
-		led_cdev->default_trigger = led_cdev->hw_control_trigger;
 	led_trigger_set_default(led_cdev);
 #endif