Hi Benjamin,
On Thu, Feb 05, 2015 at 06:06:29PM -0500, Benjamin Tissoires wrote:
> Hi Anshul,
>
> The commit 0c3e99437a66e4c869c60c2398449e6d98f3a988 in dtor/input.git/next
> tree introduce an interesting regression in libinput. The tests fail :)
>
> Actually, evemu-record and libinput switch the clock to monotonic when
> opening an input node, and the first thing that gets queued is a
> SYN_DROPPED event.
>
> However, in the libinput test suite, events are the bare minimum, and
> most of the tests contain only one event set (one EV_SYN).
> When seeing the SYN_DROPPED, the clients are supposed to drain the events
> until the next EV_SYN, and so they are losing the events that came long
> after the ioctl call.
> And in the end, the test suite does not receive any events.
>
> Removing the evdev_queue_syn_dropped() call in the ioctl handling fixes
> the test suite, and Peter suggested that maybe we should queue a
> SYN_DROPPED event iff there are events in the queue.
Does the following patch fixe it? But I would like to see libinput
tests more robust.
Thanks.
--
Dmitry
Input: evdev - do not queue SYN_DROPPED if queue is empty
From: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Reported-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
---
drivers/input/evdev.c | 34 +++++++++++++++++++++++-----------
1 file changed, 23 insertions(+), 11 deletions(-)
diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index e7cee38..f2a494a 100644
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c
@@ -108,10 +108,8 @@ static void __evdev_flush_queue(struct evdev_client *client, unsigned int type)
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 @@ static void evdev_queue_syn_dropped(struct evdev_client *client, bool flush)
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 @@ static void evdev_queue_syn_dropped(struct evdev_client *client, bool flush)
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 @@ static int evdev_set_clk_type(struct evdev_client *client, unsigned int clkid)
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 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 @@ static int evdev_handle_get_val(struct evdev_client *client,
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);
--
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