Troubleshooting DisplayPort MST Daisy Chaining with HP ProBooks and E24m G4 Monitors
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MellowPine47
Has anyone successfully daisy chained two HP E24m G4 USB-C conferencing monitors from an HP ProBook 445 G10 or ProBook 440 G11? The planned setup is ProBook USB-C to the first E24m G4, then DisplayPort Out from the first monitor to the second monitor. The laptop CPUs and integrated graphics support DisplayPort MST, and DisplayPort 1.2 or newer should support it as well, but the second monitor never displays anything. Both USB-C ports have been tested where available, along with current Windows 11 updates, laptop and graphics drivers, monitor firmware, and HP monitor drivers. The included HP USB-C cables were used initially, though higher-quality cables will also be tested. The monitors work individually, and connecting the second display directly through HDMI is possible, but a single-cable setup would be preferable. Are there specific monitor OSD, BIOS, cable, port, or resolution settings required to make MST work?
Answers
Check the ProBook BIOS for display-related settings. Some HP systems have a high-resolution display mode or DisplayPort capability toggle that can affect external monitor support. Enabling the high-resolution display option may be necessary for MST.
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Check the USB-C port specifications carefully. On some ProBook models, one port is limited to 5 Gbps while the other supports 10 or 20 Gbps, and the layout is not always intuitive. Also make sure Windows is set to extend the displays rather than duplicate them. A better-quality USB-C cable may be worth testing too.
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We use this exact arrangement across roughly a thousand desks: the E24m G4 is connected to the ProBook over USB-C, and a regular E24 G4 is connected from the E24m's DisplayPort Out. It is generally reliable. The most common problems are the DisplayPort cable not being fully inserted—the final click can take some force—and accidentally using DisplayPort In instead of DisplayPort Out on the first monitor. The ports are often labeled very subtly, so double-check them physically.
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Look through the first monitor's on-screen menu for a multi-monitor, MST, or multistream option and enable it. HP's configuration guidance also indicates that USB-C should be set to the mode that provides video plus USB 2.0. If both monitors are running at high resolution and 60 Hz, try lowering them to 30 Hz temporarily since some integrated GPUs cannot drive both displays at full bandwidth.
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