While no 3D mouse is plugged in, which for most users is always, the
hidapi backend looks for one every 3 seconds for as long as
QElectroTech runs. It asked hidapi for every HID device,
hid_enumerate(0, 0), and on Windows hidapi reads the serial number,
manufacturer and product strings of each device that matches what it
is asked for from the device itself. So every mouse, keyboard, headset
and webcam on the PC was asked for its names every 3 seconds, on the
GUI thread. Issue #1553 reports the pointer moving by itself on Windows
since the first package with this backend; nothing else in that package
talks to devices. SDL 2.0.9 polled the same way and saw freezes and a
keyboard that kept re-initialising (libsdl-org/SDL#3071).
The scan now asks for 3Dconnexion's vendor id, and for each 3D mouse
made under Logitech's id by its product id, since most other mice and
keyboards carry Logitech's id too. That is twelve hidapi calls instead
of one, but a device that does not match is no longer asked for its
names. On Linux and macOS hidapi takes the names from the system, and
one call is cheaper than twelve (on Linux, median of 200: 5 ms against
36 ms), so the scan there is unchanged.
Where the scan is filtered, a Logitech-id device that is not one of the
eleven 3D mice on the list is no longer found, even if it reports
itself as a multi-axis controller. 3Dconnexion's own mice and keyboards,
such as the CadMouse, are still asked: their vendor id is asked for as
a whole, so that new 3D mice are found without a list.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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