As discussed in the mailing list:

Right now the hid-logitech-dj driver will export one node for each
connected device, even when the device is not connected. That causes
some trouble because in userspace we don't have have any way to know if
the device is connected or not, so when we try to communicate, if the
device is disconnected it will fail.

The solution reached to solve this issue is to trigger an udev change
event when the device connects, this way userspace can just wait on
those connections instead of trying to ping the device.

Signed-off-by: Filipe Laíns <redacted>
---
 drivers/hid/hid-logitech-dj.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/hid/hid-logitech-dj.c b/drivers/hid/hid-logitech-dj.c
index 48dff5d6b605..fcd481a0be1f 100644
--- a/drivers/hid/hid-logitech-dj.c
+++ b/drivers/hid/hid-logitech-dj.c

@@ -1464,6 +1464,8 @@ static int logi_dj_dj_event(struct hid_device *hdev,
 		if (dj_report->report_params[CONNECTION_STATUS_PARAM_STATUS] ==
 		    STATUS_LINKLOSS) {
 			logi_dj_recv_forward_null_report(djrcv_dev, dj_report);
+		} else {
+			kobject_uevent(&hdev->dev.kobj, KOBJ_CHANGE);
 		}
 		break;
 	default:

-- 
2.25.1