Input: evdev - do not queue SYN_DROPPED if queue is empty
There is no point in queueing EV_SYN/SYN_DROPPED on clock type change when
there are no events in the client's queue and doing so confuses tests in
libinput package, so let's not do that.
Reported-and-tested-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index e7cee38..a18f41b 100644
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c
@@ -108,10 +108,8 @@
client->head = head;
}
-/* queue SYN_DROPPED event and flush queue if flush parameter is true */
-static void evdev_queue_syn_dropped(struct evdev_client *client, bool flush)
+static void __evdev_queue_syn_dropped(struct evdev_client *client)
{
- unsigned long flags;
struct input_event ev;
ktime_t time;
@@ -126,11 +124,6 @@
ev.code = SYN_DROPPED;
ev.value = 0;
- spin_lock_irqsave(&client->buffer_lock, flags);
-
- if (flush)
- client->packet_head = client->head = client->tail;
-
client->buffer[client->head++] = ev;
client->head &= client->bufsize - 1;
@@ -139,12 +132,21 @@
client->tail = (client->head - 1) & (client->bufsize - 1);
client->packet_head = client->tail;
}
+}
+static void evdev_queue_syn_dropped(struct evdev_client *client)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&client->buffer_lock, flags);
+ __evdev_queue_syn_dropped(client);
spin_unlock_irqrestore(&client->buffer_lock, flags);
}
static int evdev_set_clk_type(struct evdev_client *client, unsigned int clkid)
{
+ unsigned long flags;
+
if (client->clk_type == clkid)
return 0;
@@ -163,8 +165,18 @@
return -EINVAL;
}
- /* Flush pending events and queue SYN_DROPPED event.*/
- evdev_queue_syn_dropped(client, true);
+ /*
+ * Flush pending events and queue SYN_DROPPED event,
+ * but only if the queue is not empty.
+ */
+ spin_lock_irqsave(&client->buffer_lock, flags);
+
+ if (client->head != client->tail) {
+ client->packet_head = client->head = client->tail;
+ __evdev_queue_syn_dropped(client);
+ }
+
+ spin_unlock_irqrestore(&client->buffer_lock, flags);
return 0;
}
@@ -803,7 +815,7 @@
ret = bits_to_user(mem, maxbit, maxlen, p, compat);
if (ret < 0)
- evdev_queue_syn_dropped(client, false);
+ evdev_queue_syn_dropped(client);
kfree(mem);