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There is a connect event race in hidpp_probe() in these 2 lines:

	connected = hidpp_root_get_protocol_version(hidpp) == 0;
	atomic_set(&hidpp->connected, connected);

Specifically the following can happen:

1. This line from hidpp_probe() is executed:
	connected = hidpp_root_get_protocol_version(hidpp) == 0;
   and sets connected to false;

2. A connect-event packet is received and does:
	atomic_set(&hidpp->connected, true);

3. The next line from hidpp_probe() is executed:
	atomic_set(&hidpp->connected, connected);
   and sets the atomic_t back to 0 again.

4. hidpp_connect_event() runs and sees the connected device
   as disconnected because of this.

To fix this make hidpp_connect_event() query the connection status
of the device itself instead of having it rely on possibly stale
data cached in struct hidpp_device.

This series has been tested on the following devices:
Logitech Bluetooth Laser Travel Mouse (bluetooth, HID++ 1.0)
Logitech M720 Triathlon (bluetooth, HID++ 4.5)
Logitech M720 Triathlon (unifying, HID++ 4.5)
Logitech K400 Pro (unifying, HID++ 4.1)
Logitech K270 (eQUAD nano Lite, HID++ 2.0)
Logitech M185 (eQUAD nano Lite, HID++ 4.5)
Logitech LX501 keyboard (27 Mhz, HID++ builtin scroll-wheel, HID++ 1.0)
Logitech M-RAZ105 mouse (27 Mhz, HID++ extra mouse buttons, HID++ 1.0)

And by bentiss:
Logitech Touchpad T650 (unifying)
Logitech Touchpad T651 (bluetooth)
Logitech MX Master 3B (BLE)
Logitech G403 (plain USB / Gaming receiver)
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20231010102029.111003-11-hdegoede@redhat.com

Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>