On Mon, 09 Jan 2023, Uwe Kleine-König wrote:
> Hello Jürgen,
>
> On Mon, May 03, 2021 at 11:25:42AM +0200, Juergen Borleis wrote:
> > Using led_set_brightness_sync() only works for LEDs which are connected
> > via some kind of external bus like I²C or SPI. But it doesn't work for
> > the simple use case of directly connected LEDs via GPIOs.
> > Because this function only honors the led_classdev::brightness_set_blocking
> > callback. But the LED-GPIO driver registers the
> > led_classdev::brightness_set member if the GPIO can be modified directly
> > and thus, TTY triggers fail silently with -ENOTSUPP.
> >
> > With the previously used led_set_brightness() it works for both use cases.
> > This function first checks for the simple case where the GPIO can be changed
> > without additional overhead, and if it fails, does the modification via a
> > workqueue.
> >
> > Signed-off-by: Juergen Borleis <jbe@xxxxxxxxxxxxxx>
> > ---
> > drivers/leds/trigger/ledtrig-tty.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/leds/trigger/ledtrig-tty.c b/drivers/leds/trigger/ledtrig-tty.c
> > index f62db7e..af61281 100644
> > --- a/drivers/leds/trigger/ledtrig-tty.c
> > +++ b/drivers/leds/trigger/ledtrig-tty.c
> > @@ -122,12 +122,12 @@ static void ledtrig_tty_work(struct work_struct *work)
> >
> > if (icount.rx != trigger_data->rx ||
> > icount.tx != trigger_data->tx) {
> > - led_set_brightness_sync(trigger_data->led_cdev, LED_ON);
> > + led_set_brightness(trigger_data->led_cdev, LED_ON);
> >
> > trigger_data->rx = icount.rx;
> > trigger_data->tx = icount.tx;
> > } else {
> > - led_set_brightness_sync(trigger_data->led_cdev, LED_OFF);
> > + led_set_brightness(trigger_data->led_cdev, LED_OFF);
> > }
>
> This problem still exists, right?
>
> I think the right thing here is to call led_set_brightness_nosleep()
> however.
>
> Having said that, I think there are too many variants of
> led_set_brightness which makes it difficult to pick the right one.
>
> (I'm aware of
> - led_set_brightness_nosleep
> - led_set_brightness_nopm
> - led_set_brightness_sync
> - led_set_brightness
>
> and there are a few more static variants in led-core.c
> (__led_set_brightness, __led_set_brightness_blocking,
> set_brightness_delayed).)
This patch (and this response) was never sent to me.
Not a great deal I can do if I'm not aware of it.
--
Lee Jones [李琼斯]
