This article addresses a configuration requirement for daisy-chaining Dell U2415 monitors on Intel HD Graphics
Multi-Stream Transport (MST), also known as Daisy Chaining, is a new connection specification that allows multiple monitors to be connected in series with the video signal being passed from the computer to a monitor, and then from the first monitor on to the second monitor and so on. This differs from the traditional configuration of having a separate video cable run from the graphics adapter to each monitor in parallel. This simplifies the video wiring in most situations, but does have some specific configuration requirements to enable it.
Daisy chaining monitors is supported in the Display Port (DP) 1.2 specification, however, not all of the monitors to be included in the daisy chain configuration can be set to DP 1.2 due to how the Intel HD Graphics Driver functions. In order to enable Daisy chaining, the first monitor in the series (the monitor directly connected to the graphics card) must have DP 1.2 enabled in the monitor settings. Monitor number two in the chain must have DP 1.2 disabled.
The reason for this is that the Intel HD Graphics driver requires a "terminator" signal in the chain to indicate the second monitor is the last monitor in the chain in which to extend (or duplicate) the desktop to. If there are three monitors in the daisy chain, then the first two monitors would have DP 1.2 enabled and the third would be disabled, and so on.
DP1.2 enables MST streaming, leaving it off acts as a terminator for the chain to the Intel HD driver. You may extend the desktop to the first two monitors, bu can only clone any additional monitors beyond the second.
Set up for daisy chaining 3 monitors is slightly different from 2 monitors. To achieve this setup you must select in the monitors On Screen Display (OSD) the DP1.2 enable/disable feature. Set the first monitor to DP1.2 enabled, set the second monitor to DP1.2 disabled and set the third monitor to DP1.2 disabled. The first display will be your primary display and the 2nd and 3rd displays will be cloned.
Users can locate additional configuration details in the U2415 Monitor User Manual.
Article ID: SLN295251
Last Date Modified: 06/29/2018 11:16 AM
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