[PATCH v2] HID: logitech-dj: issue udev change event on device connection
From: Filipe Laíns <hidden>
Date: 2020-03-18 19:27:55
Also in:
lkml
Subsystem:
hid core layer, hid logitech drivers, the rest · Maintainers:
Jiri Kosina, Benjamin Tissoires, Linus Torvalds
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> --- v2: - Issue udev change event on the connected hid device, not on the receiver --- drivers/hid/hid-logitech-dj.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/hid/hid-logitech-dj.c b/drivers/hid/hid-logitech-dj.c
index 48dff5d6b605..282e57dd467d 100644
--- a/drivers/hid/hid-logitech-dj.c
+++ b/drivers/hid/hid-logitech-dj.c@@ -1412,6 +1412,7 @@ static int logi_dj_dj_event(struct hid_device *hdev, { struct dj_receiver_dev *djrcv_dev = hid_get_drvdata(hdev); struct dj_report *dj_report = (struct dj_report *) data; + struct dj_device *dj_dev; unsigned long flags; /*
@@ -1447,7 +1448,9 @@ static int logi_dj_dj_event(struct hid_device *hdev, spin_lock_irqsave(&djrcv_dev->lock, flags); - if (!djrcv_dev->paired_dj_devices[dj_report->device_index]) { + dj_dev = djrcv_dev->paired_dj_devices[dj_report->device_index]; + + if (!dj_dev) { /* received an event for an unknown device, bail out */ logi_dj_recv_queue_notification(djrcv_dev, dj_report); goto out;
@@ -1464,6 +1467,8 @@ 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(&dj_dev->hdev->dev.kobj, KOBJ_CHANGE); } break; default:
--
2.25.1