[PATCH libinput] evdev: Log evdev event queue overflows

[Derek Foreman]

Log a message when the kernel event queue overflows and events are dropped.
After 10 messages logging stops to avoid flooding the logs if the condition
is persistent.
---
 src/evdev.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/evdev.c b/src/evdev.c
index 1b4ce10..c786537 100644
--- a/src/evdev.c
+++ b/src/evdev.c
@@ -912,6 +912,7 @@ evdev_sync_device(struct evdev_device *device)
 static void
 evdev_device_dispatch(void *data)
 {
+	static int overflows = 0;
 	struct evdev_device *device = data;
 	struct libinput *libinput = device->base.seat->libinput;
 	struct input_event ev;
@@ -924,6 +925,15 @@ evdev_device_dispatch(void *data)
 		rc = libevdev_next_event(device->evdev,
 					 LIBEVDEV_READ_FLAG_NORMAL, &ev);
 		if (rc == LIBEVDEV_READ_STATUS_SYNC) {
+			if (overflows < 10) {
+				overflows++;
+				log_info(libinput, "Kernel evdev event queue "
+					 "overflow for %s\n", device->devname);
+				if (overflows == 10)
+					log_info(libinput, "No longer logging "
+						 "evdev event queue overflows\n");
+			}
+
 			/* send one more sync event so we handle all
 			   currently pending events before we sync up
 			   to the current state */
-- 
2.1.1