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U2518D, resolution changes to 2048x1080
I have a very annoying problem.... Every time I restart my Windows 7 machine, my U2518D monitor's screen resolution is set to 2048x1080 and 2560x1440 is not an option in the screen resolution settings. If I reinstall the Intel HD Graphics 4600 driver, the screen resolution switches to 2560x1440 as it should be. But next time I restart it goes back down to 2048x1080 and I have to reinstall the driver every time. The U2518D is connected via DisplayPort to my Z97-A motherboard as my primary monitor. I have a U2515H daisy chained to it as my secondary monitor (extended). The U2515H is always recognized at 2560x1440 resolution. Any idea what is going wrong with the U2518D or how I might fix this? I've upgraded the firmware/drivers on everything.
Thanks
DELL-Chris M
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April 16th, 2018 09:00
You should consider adding a descent PCIe x16 video card with DP out port.
* Turn the computer, U2518D, and U2515H off
* Disconnect the U2515H and all of its cabling from both the U2518D and the computer
* Turn the U2518D on, then the computer
* Use the free Intel DSA (Driver Support Assistant) utility to check and if needed install the latest Intel chipset and video GPU drivers
* Reboot the computer when done
* If needed, change the resolution to 2560x1440 60Hz. If already set to 2560x1440 60Hz, restart the computer multiple times. Does it always come back at 2560x1440 60Hz?
* If yes, now add back the U2515H as the daisy chained monitor
Motherboard DP out port --> U2518D DP to mDP cable --> U2518D mDP in port (Menu MST On)
U2518D DP out port --> U2515H DP to mDP cable --> U2515H mDP in port (Menu DP 1.2/MST Disable)
* Restart the computer when done. Do the issues reappear when adding the daisy chained U2515H?
AnorexicFabio
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April 16th, 2018 15:00
The Intel tool says drivers & chipset are up-to-date.
I've tested this and determined that if MST is set to "on" on the U2518D when Windows starts up, this problem occurs (even if U2515H is disconnected). If it's set to "off", this problem does not occur (monitors will be duplicated instead of extended). I can then change it to "on" as soon as Windows had loaded.
I previously had the monitors reversed (U2515H connected to computer, U2518D daisy chained) and didn't have this problem, but I had to reverse them for a different reason. I want to say that when I first reversed them I didn't have this problem either, but I haven't restarted the computer for a several months so I don't recall for sure.
DELL-Chris M
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April 16th, 2018 15:00
The U2518D out of box default is is DP 1.2. Change it to DP 1.1a =
* Press the Menu button
* Go to Input Source
* Select DP or mDP and hold down the button for 8 seconds. A choice should appear for DP 1.2 or DP 1.1a
* Select DP 1.1a
* Then retest
AnorexicFabio
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April 16th, 2018 18:00
Disabling DP 1.2 via that menu appears to be the same as setting MST to "off" in the Display menu - disables daisy chaining.
DELL-Chris M
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April 17th, 2018 05:00
I was told that they are two different functions? Regardless, did you do the 8 second thing, choose DP 1.1a, exit the Menu and retest?
AnorexicFabio
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April 17th, 2018 07:00
After holding for 8 seconds I get a menu that says "DP 1.2?" with enable/disable options. I can't actually move between the options, but I can press the checkmark to toggle between the two.
Disabling DP 1.2 also sets MST=off in the display menu. Setting MST=on in the display menu enables DP 1.2. So it seems to me that they're either the same or that MST requires DP 1.2 (which I think is the case). AFAIK DP 1.1a doesn't support daisy chaining, which I am trying to use.
Thanks
DELL-Chris M
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April 17th, 2018 07:00
"I want to say that when I first reversed them I didn't have this problem either"
This leads me to think the issue is the Intel HD GPU driver. I do not think the monitors are at fault here. I think the fault is with the onboard Intel HD GPU not identifying the MST/DP 1.2 setup on boot up. Which is why I stated that it would be a good idea to get a better PCIe x16 video card with DP out port.