Hi Dmitry,
Le ven. 5 mars 2021 à 10:35, Dmitry Torokhov
<dmitry.torokhov@xxxxxxxxx> a écrit :
Hi Paul,
On Fri, Mar 05, 2021 at 05:01:11PM +0000, Paul Cercueil wrote:
-static void gpio_keys_gpio_work_func(struct work_struct *work)
+static enum hrtimer_restart gpio_keys_debounce_timer(struct
hrtimer *t)
{
- struct gpio_button_data *bdata =
- container_of(work, struct gpio_button_data, work.work);
+ struct gpio_button_data *bdata = container_of(t,
+ struct gpio_button_data,
+ debounce_timer);
gpio_keys_gpio_report_event(bdata);
I am not sure how this works. As far as I know, even
HRTIMER_MODE_REL_SOFT do not allow sleeping in the timer handlers, and
gpio_keys_gpio_report_event() use sleeping variant of GPIOD API (and
that is not going to change).
Quoting <linux/hrtimers.h>, the "timer callback will be executed in
soft irq context", so sleeping should be possible.
But I guess in this case I can use HRTIMER_MODE_REL.
It seems to me that if you want to use software debounce in gpio keys
driver you need to set up sufficiently high HZ for your system. Maybe
we
could thrown a warning when we see low debounce delay and low HZ to
alert system developer.
This is exactly what we should not do. I certainly don't want to have
250+ timer interrupts per second just so that input events aren't lost,
to work around a sucky debounce implementation. Besides, if you
consider the hrtimers doc (Documentation/timers/hrtimers.rst), hrtimers
really are what should be used here.
-Paul
