The tty LED trigger uses the obsolete LED_ON & LED_OFF constants when
setting LED brightness. This is bad because the LED_ON constant is equal
to 1, and so when activating the tty LED trigger on a LED class device
with max_brightness greater than 1, the LED is dimmer than it can be
(when max_brightness is 255, the LED is very dimm indeed; some devices
translate 1/255 to 0, so the LED is OFF all the time).
Instead of directly setting brightness to a specific value, use the
led_blink_set_oneshot() function from LED core to configure the blink.
This function takes the current configured brightness as blink
brightness if not zero, and max brightness otherwise.
This also changes the behavior of the TTY LED trigger. Previously if
rx/tx stats kept changing, the LED was ON all the time they kept
changing. With this patch the LED will blink on TTY activity.
Fixes: fd4a641ac8 ("leds: trigger: implement a tty trigger")
Signed-off-by: Marek Behún <kabel@kernel.org>
Link: https://lore.kernel.org/r/20230802090753.13611-1-kabel@kernel.org
Signed-off-by: Lee Jones <lee@kernel.org>
led_set_brightness() involves scheduling a workqueue. As here the led's
brightness setting is done in context of the trigger's workqueue this is
unjustified overhead and it's more sensible to use
led_set_brightness_sync().
Fixes: fd4a641ac8 ("leds: trigger: implement a tty trigger")
Reported-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20210219133307.4840-3-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ttyname is allocated before the mutex is taken, so it must not be
unlocked in the error path.
Fixes: fd4a641ac8 ("leds: trigger: implement a tty trigger")
Reported-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20210219133307.4840-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Usage is as follows:
myled=ledname
tty=ttyS0
echo tty > /sys/class/leds/$myled/trigger
echo $tty > /sys/class/leds/$myled/ttyname
. When this new trigger is active it periodically checks the tty's
statistics and when it changed since the last check the led is flashed
once.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20210113173018.bq2fkea2o3yp6rf6@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
