linux-kernel - [PATCH] Input: gpio_keys - ensure we don't miss key-presses during resume.

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Message-ID: <20120425120849.04cee091@notabene.brown>
Date:	Wed, 25 Apr 2012 12:08:49 +1000
From:	NeilBrown <neilb@...e.de>
To:	Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc:	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] Input: gpio_keys - ensure we don't miss key-presses during
 resume.

If the latency of resume means we don't poll the key status until
after it has been released, we can lose the keypress which woke the
device.

So on each interrupt, record that a press is pending, and in that
case, report both the up and down event, ordered such that the second
event is that one that reflects the current state.

One event will normally be swallowed by the input layer if there was
no change, but the result will be that every interrupt will produce at
least one event.

Signed-off-by: NeilBrown <neilb@...e.de>

diff --git a/drivers/input/keyboard/gpio_keys.c b/drivers/input/keyboard/gpio_keys.c
index 62bfce4..961e5e1 100644
--- a/drivers/input/keyboard/gpio_keys.c
+++ b/drivers/input/keyboard/gpio_keys.c
@@ -40,6 +40,7 @@ struct gpio_button_data {
 	spinlock_t lock;
 	bool disabled;
 	bool key_pressed;
+	bool pending;
 };

 struct gpio_keys_drvdata {
@@ -335,6 +336,14 @@ static void gpio_keys_gpio_report_event(struct gpio_button_data *bdata)
 		if (state)
 			input_event(input, type, button->code, button->value);
 	} else {
+		if (type == EV_KEY && bdata->pending) {
+			/* Before reporting the observed state, report the
+			 * alternate to be sure that a change is seen.
+			 */
+			bdata->pending = 0;
+			input_event(input, type, button->code, !state);
+			input_sync(input);
+		}
 		input_event(input, type, button->code, !!state);
 	}
 	input_sync(input);
@@ -361,6 +370,7 @@ static irqreturn_t gpio_keys_gpio_isr(int irq, void *dev_id)

 	BUG_ON(irq != bdata->irq);

+	bdata->pending = true;
 	if (bdata->timer_debounce)
 		mod_timer(&bdata->timer,
 			jiffies + msecs_to_jiffies(bdata->timer_debounce));

Download attachment "signature.asc" of type "application/pgp-signature" (829 bytes)