1 of 1 people found this helpful
Seeing as you only seem to have a single "true" DaisyChain monitor (the Dell U2415b) you technically should only be able to connect a maximum of 2 monitors. Except for the "last" monitor on this connection, both the other monitors need to also support MST 1.2 tech. As such you would need to have 2x Dell U2415b MST monitors in order to properly get 3 screens working. I realize that you can get them all working when using 14.12 Omega, but that is not a fully supported format and would not work on a stable basis and thus cannot be supported across the board.
You can find more information about the rules for connecting multiple displays using the built in MST connectors in the User Manual for your monitor at:
Here is a screenshot of the User Manual for the monitor you are using (U2415b) from page 11 with the rules for getting mu
Thank you tekkiaussie for your response. I understand that configuration, however, (and I should have stated this in my original question) The AMD card I use (Radeon HD 7440) has a DVI port, and a Displayport. So, the U2415b is daisy chaining only 1 of those other monitors and the 3rd one is using DVI. In Omega, the Displayport is recognized properly and daisy chains to the second DP monitor along with the DVI monitor giving me 3. In 15.04 (or 14.04 with driver version 15.3) Only the U2415b and the DVI monitor are detected. I do not believe this breaks the supported methods as you described.