Causes
- KVM only routes USB over the USB-C (DP Alt Mode) input, not HDMI/DP — the M27Q's built-in KVM shares one keyboard and mouse between two machines, but the USB data path follows whichever display input the OSD is set to share with USB. If you are trying to switch between the two ports over HDMI or DisplayPort rather than the USB-C upstream, or the OSD's input isn't linked to the USB hub, the keyboard/mouse simply stay attached to the first machine.
- The OSD Input / KVM auto-switch option is not enabled — the OSD has a setting that tells the monitor to switch input (and the shared USB) when a selected source sends a signal. Unless this auto-input-switch/KVM toggle is on, pressing a hotkey or changing input on the desktop won't move the shared keyboard and mouse over to the second PC.
- Wrong or non-DP-Alt-Mode USB-C cable to the console/second machine — to carry both the 2560x1440 image and USB device data, the M27Q's USB-C must be connected with a USB-C cable that supports DisplayPort Alt Mode and data. A charge-only or non-Alt-Mode cable shows video on some ports but never routes the KVM's USB devices, so switching silently fails.
- USB peripherals plugged into the wrong hub port — the M27Q has two USB 3.0 downstream ports used by the KVM. Devices wired to the wrong set, or into a powered USB hub that sits ahead of the monitor, may stay bound to one host or not be seen at all, making the KVM appear broken.
- Outdated OSD firmware or stale settings — a buggy/older M27Q firmware can mishandle input switching; some units need an OSD reset or firmware update before the KVM toggles reliably, especially when waking a connected laptop from sleep.
How to Fix
- Identify your two hosts and correct the wiring — decide PC A and PC B. Connect PC A over DisplayPort or HDMI and PC B over the USB-C input (or vice-versa as your ports allow). If BOTH hosts are HDMI/DP, the M27Q's dedicated KVM won't route USB between them the way users expect — for two non-USB-C desktop PCs, add a standalone KVM switch instead, since the shared USB follows the USB-C upstream.
- Plug the shared keyboard and mouse into the M27Q's USB 3.0 hub ports — ensure the keyboard/mouse (or receiver dongle) are connected to the two USB ports on the monitor, not to a PC. These are the ports the KVM routes to whichever host is active.
- Enable the KVM and Input auto-switch in the OSD — open the OSD by pressing the menu/joystick button, go to the System or Input menu, and turn on the KVM switch and the Auto Input Switch / USB-switch option for the USB-C input. Save, then toggle between inputs using the OSD joystick or button to confirm the shared devices change hosts.
- Use a proper USB-C DP-Alt-Mode cable for the console/laptop side — swap the USB-C link to a cable that explicitly supports DisplayPort Alt Mode and USB data (not just charging). Confirm the laptop/console port can output DP Alt Mode at all; many budget laptops disable it on one USB-C port. If the second device relies on HDMI, you lose KVM routing and should use a true USB switch for its peripherals.
- Update the OSD firmware and factory-reset — check gigabyte.com for the M27Q firmware/OSD updater, install the latest version, then choose Factory Reset in the OSD to clear stale input-switching state. Reboot both hosts and retest the toggle.
- Run the KVM test straight through — with both machines powered, attach one device to each input, set the OSD to KVM auto-switch, and press the input hotkey/button. If switching works, re-add your powered USB hubs and repeat; if it fails only when a hub is inserted, remove the extra hub and accept the minor re-plug trade-off.