If last event dropped in the old queue was EV_SYN/SYN_REPORT, then lets
generate EV_SYN/SYN_REPORT immediately after queing EV_SYN/SYN_DROPPED
so that clients would not ignore next valid full packet events.
Signed-off-by: Aniroop Mathur <a.mat...@samsung.com>
Difference from v8:
Added check for handling EVIOCG[type] ioctl for queue empty case
---
drivers/input/evdev.c | 52 ++++++++++++++++++++++++++++++++++++++-------------
1 file changed, 39 insertions(+), 13 deletions(-)
diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index e9ae3d5..69407ff 100644
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c
@@ -156,7 +156,12 @@ static void __evdev_flush_queue(struct evdev_client
*client, unsigned int type)
static void __evdev_queue_syn_dropped(struct evdev_client *client)
{
struct input_event ev;
+ struct input_event *last_ev;
ktime_t time;
+ unsigned int mask = client->bufsize - 1;
+
+ /* capture last event stored in the buffer */
+ last_ev = &client->buffer[(client->head - 1) & mask];
time = client->clk_type == EV_CLK_REAL ?
ktime_get_real() :
@@ -170,13 +175,28 @@ static void __evdev_queue_syn_dropped(struct evdev_client
*client)
ev.value = 0;
client->buffer[client->head++] = ev;
- client->head &= client->bufsize - 1;
+ client->head &= mask;
if (unlikely(client->head == client->tail)) {
/* drop queue but keep our SYN_DROPPED event */
- client->tail = (client->head - 1) & (client->bufsize - 1);
+ client->tail = (client->head - 1) & mask;
client->packet_head = client->tail;
}
+
+ /*
+ * If last packet was completely stored, then queue SYN_REPORT
+ * so that clients would not ignore next valid full packet
+ */
+ if (last_ev->type == EV_SYN && last_ev->code == SYN_REPORT) {
+ last_ev->time = ev.time;
+ client->buffer[client->head++] = *last_ev;
+ client->head &= mask;
+ client->packet_head = client->head;
+
+ /* drop queue but keep our SYN_DROPPED & SYN_REPORT event */
+ if (unlikely(client->head == client->tail))
+ client->tail = (client->head - 2) & mask;
+ }
}
static void evdev_queue_syn_dropped(struct evdev_client *client)
@@ -218,7 +238,7 @@ static int evdev_set_clk_type(struct evdev_client *client,
unsigned int clkid)
spin_lock_irqsave(&client->buffer_lock, flags);
if (client->head != client->tail) {
- client->packet_head = client->head = client->tail;
+ client->packet_head = client->tail = client->head;
__evdev_queue_syn_dropped(client);
}
@@ -231,22 +251,24 @@ static int evdev_set_clk_type(struct evdev_client
*client, unsigned int clkid)
static void __pass_event(struct evdev_client *client,
const struct input_event *event)
{
+ unsigned int mask = client->bufsize - 1;
+
client->buffer[client->head++] = *event;
- client->head &= client->bufsize - 1;
+ client->head &= mask;
if (unlikely(client->head == client->tail)) {
/*
* This effectively "drops" all unconsumed events, leaving
- * EV_SYN/SYN_DROPPED plus the newest event in the queue.
+ * EV_SYN/SYN_DROPPED, EV_SYN/SYN_REPORT (if required) and
+ * newest event in the queue.
*/
- client->tail = (client->head - 2) & (client->bufsize - 1);
-
- client->buffer[client->tail].time = event->time;
- client->buffer[client->tail].type = EV_SYN;
- client->buffer[client->tail].code = SYN_DROPPED;
- client->buffer[client->tail].value = 0;
+ client->head = (client->head - 1) & mask;
+ client->packet_head = client->tail = client->head;
+ __evdev_queue_syn_dropped(client);
- client->packet_head = client->tail;
+ client->buffer[client->head++] = *event;
+ client->head &= mask;
+ /* No need to check for buffer overflow as it just occurred */
}
if (event->type == EV_SYN && event->code == SYN_REPORT) {
@@ -920,6 +942,7 @@ static int evdev_handle_get_val(struct evdev_client *client,
int ret;
unsigned long *mem;
size_t len;
+ bool is_queue_empty;
len = BITS_TO_LONGS(maxbit) * sizeof(unsigned long);
mem = kmalloc(len, GFP_KERNEL);
@@ -933,12 +956,15 @@ static int evdev_handle_get_val(struct evdev_client
*client,
spin_unlock(&dev->event_lock);
+ if (client->head == client->tail)
+ is_queue_empty = true;
+
__evdev_flush_queue(client, type);
spin_unlock_irq(&client->buffer_lock);
ret = bits_to_user(mem, maxbit, maxlen, p, compat);
- if (ret < 0)
+ if (ret < 0 && !is_queue_empty)
evdev_queue_syn_dropped(client);
kfree(mem);
--
2.6.2
